1 Bernard C., Leçons sur les Phénomènes de la Vie. Paris, 1885, i., 22–64.

2 Driesch, H., The Science and Philosophy of the Organism. 2 vols. The Gifford Lectures, 1907 and 1908.

3 v. Uexküll, J., Bausteine zu einer biologischen Weltanschauung. München, 1913.

4 v. Uexküll, J., Bausteine zu einer biologischen Weltanschauung. München, 1913, p. 216.

5 de Vries, H., Die Muta­tionstheorie. Leipzig, 1901.

6 This difficulty is also felt by mechanistic writers like Child, who on page 12 of his recent book on Senescence and Rejuvenescence (Chicago, 1915) makes the following remarks: “These theories of Weismann do not account satisfactorily for the peculiarly constant course and character of development and morphogenesis. If we follow them to their logical conclusion, which their authors have not done, we find ourselves forced to assume the existence of some sort of controlling and co-ordinating principle outside the units themselves and superior to them. If the units constitute the physico­chemical basis of life, as their authors maintain, then this controlling principle, since it is an essential feature of life, must of necessity be something which is not physico­chemical in nature. In short these theories lead us in the final analysis to the same conclusion as that reached by the neovitalists. If we are not content to accept this conclusion we must reject the theories.” These last sentences do not exhaust all the possibilities, since the writer is trying to show in this book that the widest acceptance of the chromo­some theory of heredity is compatible with a consistent physico­chemical concep­tion of the organism as a whole.

7 Pasteur, L., Annal. d. Chim. et d. Physique, 1862, 3 sér., lxiv., 1.

8 Winogradsky, S., “Die Nitrifica­tion,” Handb. d. tech. Mykol., 1904–06, iii., 132.

9 Winogradsky, loc. cit., p. 163 and ff.

10 Godlewski, E., Anz. d. Akad. d. Wissensch. in Krakau, 1892, 408; 1895, 178.

11 Nathanson, Mitteil. d. zool. Sta­tion, Neapel, 1902.

12 Beijerinck, M., Folia Microbiologica, 1914, iii., 91.

13 Ernst, A., The New Flora of the Volcanic Island of Krakatau, Cambridge, 1908.

14 Euler, H., Pflanzenchemie, 1909, ii. and iii., 140.

15 This fact was thoroughly established by Mendel and Osborne. A summary of their work is given in Underhill, F. P., Physiology of the Amino Acids, 1916.

16 Van Slyke, D. D., and Cullen, G. E., Jour. Biol. Chem., 1914, xix., 141.

17 Hill, C., Jour. Chem. Soc., 1898, lxxiii., 634.

18 Armstrong, E. F., Proc. Royal Soc., 1905, B. lxxvi., 592.

19 Kastle, J. H., and Loevenhart, A. S., Am. Chem. Jour., 1900, xxiv., 491.

20 Taylor, A. E., Univ. Cal. Pub., 1904, Pathology, i., 33; Jour. Biol. Chem., 1906, ii., 87.

21 Bradley, H. C., Jour. Biol. Chem., 1913, xiii., 407.

22 This would lead to the idea that the enzymes in the cell also synthetize molecules of their own kind, or that, in other words, the synthetic processes in the cell are of the nature of autocatalysis. Loeb, Der chemische Character des Befruchtungsvorgangs, Leipzig, 1908. Robertson, T. B., Arch. f. Entwicklngsmech., 1908, xxv., 581; xxvi., 108; 1913, xxxvii., 497; Am. Jour. Physiol., 1915, xxxvii., 1; Robertson and Wasteneys, H., Arch. f. Entwicklngsmech., 1913, xxxvii., 485. Ostwald, Wo., Über die zeitlichen Eigenschaften der Entwicklungsvorgänge, Leipzig, 1908.

23 Loeb, Leo, Jour. Med. Res., 1901, vi., 28; Arch. f. Entwicklngsmech., 1907, xxiv., 655.

24 Loeb, Leo, Über die Entstehung von Bindegewebe, Leucocyten und rothen Blutkörperchen aus Epithel und über eine Methode isolierte Gewebsteile zu züchten. Chicago, 1897.

25 While this has been demonstrated thus far only for connective-tissue cells it may be true also for other cells.

26 Arrhenius, S., Worlds in the Making, London and New York, 1908, p. 212.

27 White, J., Proc. Roy. Soc., 1909, B, lxxxi., 417.

28 Macfadyen, A., Proc. Roy. Soc., 1903, lxxi., 76.

29 Becquerel, P., Revue générale des Sciences, 1914, xxv., 559.

30 Winogradsky, S., Beiträge zur Morphologie und Physiologie der Bacterien. Leipzig, 1888.

31 Johannsen, W., Elemente der exacten Erblichkeitslehre. 2d ed., 1913.

32 Murphy, J. B., Jour. Exper. Med., 1913, xvii., 482; 1914, xix., 181; xix., 513; Murphy and Morton, J. J., Jour. Exper. Med., 1915, xxii., 204.

33 The reader is referred to Morgan’s book on Regenera­tion (New York, 1901), for the literature on this subject.

34 Baur, E., Einführung in die experi­mentelle Vererbungslehre. Berlin, 1911, p. 232.

35 Literature on this subject in Chapter IV.

36 Loeb, J., King, W. O. R., and Moore, A. R., Arch. f. Entwicklngsmech., 1910, xxix., 354.

37 Moenkhaus, W. J., Am. Jour. Anat., 1904, iii., 29.

38 Loeb, J., Jour. Morphol., 1912, xxiii., 1.

39 Landois, L., Zur Lehre von der Bluttransfusion. Leipzig, 1875.

40 This is probably true only within the limits of exactness used in these experi­ments.

41 Friedenthal, H., “Experimenteller Nachweis der Blutverwandtschaft.” Arch. f. Physiol., 1900, 494.

42 Uhlenhuth, P., and Steffenhagen, K., Kolle-Wassermann, Handb. d. pathol. Mikroorg., 2nd Ed., 1913, iii., 257.

43 Nuttall, George H. F., Blood Immunity and Blood Rela­tionship, Cambridge Univ. Press, 1904.

44 Nuttall, Blood Immunity and Blood Rela­tionship, pp. 319 and 320.

45 Nuttall, pp. 345 and 346.

46 Welsh, D. A., and Chapman, H. G., Jour. Hygiene, 1910, x., 177.

47 Magnus, W., and Friedenthal, H., Ber. d. deutsch. bot. Gesellsch., 1906, xxiv., 601.

48 Richet, C., L’anaphylaxie. Paris, 1912.

49 Quoted from Wells, H. G., Jour. Infect. Diseases, 1908, v., 449.

50 Ibid., 1911, ix., 147.

51 Gay, F. P., and Robertson, T. B., Jour. Biol. Chem., 1912, xii., 233.

52 Fitzgerald, J. G., and Leathes, J. B., Univ. Cal. Pub., 1912, “Pathology,” ii., 39.

53 Bradley, H. C., and Sansum, W. D., Jour. Biol. Chem., 1914, xviii., 497.

54 Reichert, E. T., and Brown, A. P., “The Differentia­tion and Specificity of Corresponding Proteins and other Vital Substances in Rela­tion to Biological Classifica­tion and Organic Evolu­tion.” Carnegie Institu­tion Publica­tion No. 116, Washington, 1909.

55 Uhlenhuth, Das biologische Verfahren zur Erkennung und Unterscheidung von Menschen und Tierblut, Jena, 1905, p. 102.

56 Moss, W. L., Johns Hopkins Hospital Bulletin, 1910, xxi., 62.

57 Taylor, A. E., Jour. Biol. Chem., 1908, v., 311.

58 Wells, H. G., Jour. Infect. Diseases, 1911, ix., 166.

59 Loeb, J., and Bancroft, F. W., Jour. Exper. Zoöl., 1912, xii., 381.

60 Loeb, J., Arch. f. d. ges. Physiol., 1903, xcix., 323; 1904, civ., 325; Arch. f. Entwcklngsmech., 1910, xxx., II., 44; 1914, xl., 310; Science, 1914, xl., 316.

61 Godlewski, E., Arch. f. Entwcklngsmech., 1906, xx., 579.

62 Kupelwieser, H., Arch. f. Entwcklngsmech., 1909, xxvii., 434; Arch. f. Zellforsch., 1912, viii., 352.

63 See Chapter II.

64 Loeb, J., Science, 1914, xl., 316; Am. Naturalist, 1915, xlix., 257.

65 Loeb, Arch. f. Entwcklngsmech., 1914, xl., 310.

66 Godlewski, E., Arch. f. Entwcklngsmech., 1911, xxxiii., 196.

67 Herlant, M., Anat. Anzeiger, 1912, xlii., 563.

68 Loeb, J., Jour. Exper. Zoöl., 1914, xvii., 123.

69 Lillie, F. R., Jour. Exper. Zoöl., 1914, xvi., 523.

70 Loeb, J., Am. Naturalist, 1915, xlix., 257.

71 Lillie, F. R., Science, 1913, xxxviii., 524; Jour. Exper. Zoöl., 1914, xvi., 523; Biol. Bull., 1915, xxviii., 18.

72 Lillie, F. R., loc. cit.

73 Loeb, J., Jour. Exper. Zoöl., 1914, xvii., 123; Am. Naturalist, 1915, xlix., 257.

74 Loeb, J., Arch. f. Entwcklngsmech., 1907, xxii., 479; Artificial Parthenogenesis and Fertiliza­tion, Chicago, 1913, p. 240.

75 Loeb, J., Science, 1913, xxxviii., 749; Arch. f. Entwcklngsmech., 1914, xxxviii., 277; Wasteneys, H., Jour. Biol. Chem., 1916, xxiv., 281.

76 Loeb, J., Am. Naturalist, 1915, xlix., 257.

The writer may be permitted to illustrate by a special case his reason for declining to accept Ehrlich’s side-chain theory. Ehrlich and Sachs found that if to a given mass of toxin small quantities of antitoxin are added successively the first fraction added neutralized more than the later fractions; and on the basis of this reasoning Ehrlich concluded that ten different toxins were contained in the diphtheria toxin. Arrhenius showed that the same phenomenon can be obtained when a weak base like NH₄OH is neutralized by a weak acid (e. g., boric acid); hence we should assume that NH₄OH consists of ten different forms of ammonia. Both cases, the satura­tion of toxin with antitoxin and ammonia with boric acid are equilibrium phenomena. (Arrhenius, S., Quantitative Laws in Biological Chemistry, London, 1915.)

77 Castle, W. E., Bull. Mus. Comp. Zoöl., Harvard, 1896, xxvii., 203.

78 Morgan, T. H., Jour. Exper. Zoöl., 1904, i., 135; Arch. f. Entwcklngsmech., 1910, xxx., 206.

79 Fuchs, H. M., Jour. Genet., 1915, iv., 215.

80 Quoted from Fuchs.

81 Correns, C., Biol. Centralbl., 1913, xxxiii., 389.

82 Pfeffer, Untersuchungen aus dem botanischen Institut zu Tübingen, 1881–1885, i., 363.

83 Bruchmann, H., Flora, 1909, ic., 193.

84 The substitu­tion of well-known physico­chemical agencies for the mysterious action of the spermato­zoön was the task the writer set himself in this work and not the explana­tion of natural parthenogenesis, as the author of a recent text-book seems to assume.

85 Loeb, J., Am. Jour. Physiol., 1899, iii., 135; 1900, iii., 434.

86 Loeb, J., Artificial Parthenogenesis and Fertiliza­tion, Chicago, 1913. The reader is referred to this book for the literature on the subject.

87 The reader will find a descrip­tion of the development of this egg in the next chapter.

88 The reader is referred for details to the writer’s book on the subject.

89 Robertson, T. B., Arch. f. Entwcklngsmech., 1912, xxxv., 64.

90 Loeb, J., Über den chemischen Charakter des Befruchtungsvorgangs, etc., Leipzig, 1908.

91 v. Knaffl, E., Arch. f. d. ges. Physiol., 1908, cxxiii., 279.

92 Loeb, J., Artificial Parthenogenesis and Fertiliza­tion, p. 255.

93 It has been stated by several writers that the eggs of the sea urchin can no longer form the fertiliza­tion membrane when the jelly surrounding the egg is dissolved. The writer has found that if the jelly surrounding the eggs of Strongylo­centrotus purpuratus is dissolved by acid the eggs still form a fertiliza­tion membrane upon the entrance of a spermato­zoön.

94 Loeb, J., Artificial Parthenogenesis and Fertiliza­tion, 1913, p. 250 and ff.

95 Delage, Y., Arch. d. Zoöl. expér. et gén., 1902, x., 213; 1904, ii., 27; 1905, iii., 104.

96 Lillie, R. S., Jour. Biol. Chem., 1916, xxiv., 233.

97 It is necessary to call atten­tion to the fact that sugar solu­tions of a high concentra­tion (e. g., m solu­tions) have a much higher osmotic pressure than that which they should have theoretically (Lord Berkeley and Hartley). Delage by ignoring this fact has misinterpreted his experi­ments with sugar solu­tions. See Lloyd, D. J., Arch. f. Entwcklngsmech., 1914, xxxviii., 402.

98 Loeb, J., and Wasteneys, H., Jour. Biol. Chem., 1913, xiv., 517; Biochem. Ztschr., 1913, lvi., 295.

99 Loeb, J., Biochem. Ztschr., 1906, ii., 81.

100 Loeb, J., Arch. f. d. ges. Physiol., 1906, cxiii., 487; Biochem. Ztschr., 1910, xxvi., 279, 289; xxvii., 304; xxix., 80; Arch. f. Entwcklngsmech., 1914, xl., 322.

101 Herlant, M., Arch. de Biol., 1913, xxviii., 505.

102 It is also important to remember that the forma­tion of astrospheres after mere membrane forma­tion occurs considerably more slowly than if the egg has also received a treatment with a hypertonic solu­tion.

103 The writer found that the eggs of Fundulus will segment a number of times even if all the oxygen has apparently been removed.

104 Loeb, J., Biochem. Ztschr., 1906, ii., 183.

105 Thus the treatment of an unfertilized egg without membrane with a hypertonic solu­tion combines two effects, first the general cytolytic altera­tion of the cortical layer of the membrane and the corrective effect of the hypertonic solu­tion. The former effect raises the rate of oxida­tions in the egg, the latter does not.

106 Warburg, O., Sitzungsber. d. Heidelberger Akad. d. Wissnsch., B. 1914.

107 Loeb, J., Biochem. Ztschr., 1906, ii., 87.

108 Unless the egg is left so long in the pure NaCl solu­tion that its permeability is increased.

109 Lillie, R. S., Jour. Morphol., 1911, xxii., 695; Am. Jour. Physiol., 1911, xxvii., 289.

110 McClendon, J. F., Publica­tions of the Carnegie Institu­tion, No. 183, 125; Am. Jour. Physiol., 1910, xxvii., 240.

111 Gray, J., Proc. Cambridge Philosophical Society, 1913, xvii., 1.

112 R. Lillie has recently shown that in a hypotonic solu­tion water diffuses more rapidly into a fertilized than into an unfertilized egg. This is exactly what one should expect since the unfertilized egg is not only surrounded by the cortical layer but also by a thick layer of jelly both of which are lacking in the fertilized egg. It is difficult to understand how this observa­tion can throw any light on the mechanism of development, since water diffuses rapidly enough into the unfertilized egg.

113 Delage, Y., Compt. rend. Acad. Sc., 1909, cxlviii., 453.

114 Since this was written, two more of the partheno­genetic frogs over a year old died. Both were males.

115 Loeb, J., Artificial Parthenogenesis and Fertiliza­tion, Chicago, 1913.

116 Driesch, H., Science and Philosophy of the Organism. London, 1908 and 1909.

117 Boveri, Th., Verhandl. d. physik.-med. Gesellsch., Würzburg, 1901, xxxiv., 145.

118 Lyon, E. P., Arch. f. Entwcklngsmech., 1907, xxiii., 151; Morgan, T. H., and Spooner, G. B., ibid., 1909, xxviii., 104; Morgan, Jour. Exper. Zoöl., 1910, ix., 594; Conklin, E. G., ibid., 1910, ix., 417; Lillie, F. R., Biol. Bull., 1909, xvi., 54.

119 Driesch, H., Ztschr. f. wissnsch. Zoöl., 1891, liii., 160.

120 Loeb, J., Arch. f. Entwcklngsmech., 1909, xxvii., 119.

121 Driesch, H., Arch. f. Entwcklngsmech., 1900, x., 361.

122 Driesch, H., Arch. f. Entswcklngsmech., 1902, xiv., 500.

123 Boveri, Th., Verhandl. d. physik. med. Gesellsch., Würzburg, N.F., 1901, xxxiv., 145.

124 v. Uexküll makes in his last book (Bausteine zu einer biologischen Weltanschauung, München, 1913, p. 24) the following statement: “Driesch succeeded in showing that the germ cell has no trace of a machine-like structure but consists entirely of equivalent parts.” This is not correct.

125 Loeb, J., and Beutner, R., Biochem. Ztschr., 1912, xli., 1; xliv., 303; 1913, li., 288; li., 300; 1914, lix., 195.

126 Loeb, J., The Dynamics of Living Matter. New York, 1906. Introductory Remarks.

127 Roux, W., Virchow’s Archiv, 1888, cxiv., 113.

128 Morgan, T. H., Embryology of the Frog. New York.

129 Crampton, H. E., New York Academy of Sciences, 1894; Kofoid, C. A., Proc. Am. Acad. Arts and Sciences, 1894, xxix.

130 Conklin, E. G., Anat. Anzeig., 1903, xxiii., 577; Heredity and Environment in the Development of Man. Princeton, 1915, p. 171.

131 Wilson, E. B., Science, 1904, xx., 748; Jour. Exper. Zoöl., 1904, i., 1, 197.

132 The reader will notice the absence of “regula­tion.”

133 Conklin, E. G., Heredity and Environment in the Development of Man. Princeton University Press, 1915. The reader is referred to this book for the literature and main facts on the structure of the egg; it should also be stated that Conklin’s book is one of the best introduc­tions to modern biology in the English literature.

134 Conklin, E. G., loc. cit., p. 117.

135 Loeb, J., Jour. Morphol., 1893, xiii., 161; The Mechanistic Concep­tion of Life. Chicago, 1912, p. 106.

136 Driesch, H., Science and Philosophy of the Organism, i., p. 104.

137 Herbst, C., Formative Reize in der tierischen Ontogenese. Leipzig, 1901.

138 Braus, H., Münchener Med. Wochnschr., 1903, 1 (II.), No. 47, p. 2076.

139 Nussbaum, M., Arch. f. mikroscop. Anat., 1886, xxvi., 485.

140 It must not be overlooked that in bacteria and the blue algæ no distinct differentia­tion into nucleus and protoplasm can be shown. To these organisms, therefore, the experi­ments of Nussbaum cannot be applied.

141 Loeb, J., Arch. d. f. ges. Physiol., 1893, lv., 525.

142 v. Sachs, J., “Stoff und Form der Pflanzenorgane,” Gesammelte Abhandlungen, 1892, ii., 1160. Arbeiten a. d. bot. Inst. Würzburg, 1880–82.

143 Goebel, K., Einleitung in die experi­mentelle Morphologie der Pflanzen, 1908.

144 Loeb, J., Untersuchungen zur physiologischen Morphologie der Tiere. I. Heteromorphose. Würzburg, 1891. II. Organbildung und Wachsthum. 1892. Reprinted in Studies in General Physiology. Chicago, 1906.

145 Gudernatsch, J. F., Zentralbl. f. Physiol., 1912, xxvi., 323; Arch. f. Entwcklngsmech., 1912, xxxv., 457; Am. Jour. Anat., 1914, xv., 431.

146 Morse, M., Jour. Biol. Chem., 1914, xix., 421.

147 Loeb, J., Arch. f. Entwcklngsmech., 1897, iv., 502.

148 Uhlenhuth, E., ibid., 1913, xxxvi., 211.

149 Loeb, Leo, Zentralbl. f. allg. Path. u. path. Anat., 1907, xviii., 563; Zentralbl. f. Physiol., 1908, xxii., 498; 1909, xxiii., 73; 1910, xxiv., 203; Arch. f. Entwcklngsmech., 1909, xxvii., 89, 463; Jour. Am. Med. Assoc., 1908, l., 1897; 1909, liii., 1471.

150 Quoted from M. Caullery, Les Problèmes de la Sexualité, Paris, 1913, p. 126.

151 Smith, Geoffrey, Proc. Roy. Soc., B. 1915, lxxxviii., 418.

152 Loeb, J., Bot. Gazette, 1915, lx., 249.

153 With larger leaves the experi­ment may also succeed in moist air.

154 Loeb, J., Untersuchungen zur physiologischen Morphologie. I. Heteromorphose. 1891. II. Organbildung und Wachsthum. Würzburg, 1892.

155 Bickford, E. E., Jour. Morphol., 1894, ix., 417.

156 Driesch, H., Science and Philosophy of the Organism, i., 127.

157 Child, C. M., “Die physiologische Isola­tion von Teilen des Organismus,” Roux’s Vorträge und Aufsätze, Leipzig, 1911.

158 Loeb, J., “Untersuchungen zur physiologischen Morphologie der Tiere.”

159 Morgan, T. H., Regenera­tion, New York, 1901.

160 Bardeen, C. R., Am. Jour. Physiol., 1901, v., 1; Arch. f. Entwcklngsmech., 1903, xvi., 1.

161 Przibram, H., Arch. f. Entwcklngsmech., 1901, xi., 329.

162 Child, C. M., Senescence and Rejuvenescence. Chicago, 1915.

163 Loeb, J., Am. Jour. Physiol., 1900, iv., 60.

164 The writer quotes this after Driesch.

165 Driesch, H., Arch. f. Entwcklngsmech., 1902, xiv., 247.

166 One author, Miss Thatcher, in trying to repeat these observa­tions, did not notice the total collapse of the tissues and concluded that my observa­tions must have been wrong. The writer is fairly certain that his observa­tions were correct.

167 Not yet published.

168 v. Sachs, J., “Physiologische Notizen,” vi., Flora, 1893.

169 Ibid., ix., 425, Flora, 1895.

170 Morgan, T. H., Arch. f. Entwcklngsmech., 1895, ii., 81; 1901, xiii., 416; 1903, xvi., 117.

171 Driesch, H., Arch. f. Entwcklngsmech., 1898, vi., 198; 1900, x., 361.

172 Delage, Y., Arch. Zoöl. expér., 1899, vii., 383.

173 Driesch, H., Arch. f. Entwcklngsmech., 1905, xix., 648.

174 Loeb, Leo, Arch. f. Entwcklngsmech., 1898, vi., 297.

175 Spain, K. C., and Loeb, Leo, Jour. Exper. Med., 1916, xxiii., 107; Loeb, L., and Addison, W. H. F., Arch. f. Entwcklngsmech., 1911, xxxii., 44; 1913, xxxvii., 635.

176 The excessive forma­tion of epithelial cells in the healing of wounds has led the older pathologists to the generaliza­tion that if something is removed in the body an excessive compensa­tion will take place. The forma­tion of antibodies has even been explained on this basis by Weiggert and Ehrlich in their side-chain theory. As a matter of fact, this generaliza­tion is entirely incorrect and in regenera­tion of starfish, actinians, flatworms, annelids, and possibly in all forms the reverse is true; e. g., if we cut off the anterior half of the body in Cerianthus less is reproduced than was cut away namely only tentacles and the mouth, but not the missing piece of the body. Weiggert’s concep­tion of regenera­tion was probably based on the phenomenon of the healing of wounds, but the excessive epithelium forma­tion in this case is not the expression of a general law of regenera­tion but of the peculiar mechanical condi­tions which lead to mitoses. It would be a very strange coincidence indeed if a theory of antibody forma­tion based on such an erroneous generaliza­tion should be correct.

177 Loeb, Arch. f. Entwcklngsmech., 1914, xxxviii., 277.

178 Wasteneys, H., Jour. Biol. Chem., 1916, xxiv., 281.

179 F. Lillie thinks that the KCN in this experi­ment merely inhibits the change of the cortical layer necessary for development. This is contradicted by two facts: first, the writer has shown in 1906 that KCN does not inhibit the membrane forma­tion, and, second, the eggs will not return to the resting stage when put back into sea water too soon; in that case they will disintegrate. This shows that in the KCN something more happens than the mere block to disintegra­tion.

180 Loeb, J., Untersuchungen zur physiologischen Morphologie der Tiere. II. Organbildung und Wachsthum. Würzburg, 1892.

181 Loeb, J., Die chemische Entwicklungserregung des tierischen Eies. Berlin, 1909.

182 McClung, C. E., “The Accessory Chromosome—Sex Determinant?” Biol. Bull., 1902, iii., 43.

183 Wilson, E. B., “Studies on Chromosomes,” Jour. Exper. Zoöl., 1905, ii., 371, 507; 1906, iii., 1; 1909, vi., 69, 147; 1910, ix., 53; 1912, xiii., 345. “Croonian Lecture,” 1914, Proc. Roy. Soc., B. lxxxviii., 333.

184 Doncaster, L., The Determina­tion of Sex. Cambridge, 1914.

185 Morgan, T. H., Heredity and Sex. New York, 1913.

186 Bridges, C. B., Genetics, 1916, i., 1.

187 Boveri, Th., Arch. f. Entwcklngsmech., 1915, xlii., 264.

188 Boveri, Th., Verhand. d. phys.-med. Gesellsch. Würzburg, 1911, xli., 85. Schleip, W., Ber. d. naturf. Gesellsch., Freiburg i. Br., 1911, xix.

189 Correns, C., Biol. Centralbl., 1916, xxxvi., 12.

190 Baltzer, F., Mitteil. d. zoölog. Sta­tion, Neapel, 1914, xxii.

191 Caullery, M., Les Problèmes de la Sexualité. Paris, 1913.

192 Goodale, H. D., Biol. Bull., 1916, xxx., 286.

193 Lillie, F., Science, 1916, xliii., 611.

194 Janda, V., Arch. f. Entwcklngsmech., 1912, xxxiii., 345; xxxiv., 557.

195 Goldschmidt, R., Proc. Nat. Acad. Sc., 1916, ii., 53; Ztschr. induct. Abstammungslehre, 1912, vii., and 1914, xi.

196 This account of Marchal’s beautiful experi­ments is taken from Caullery, M., Les Problèmes de la Sexualité. Paris, 1913.

197 Whitney, D. D., Science, 1916, xliii., 176.

198 Shull, A. F., and Ladoff, S., Science, 1916, xliii., 177.

199 Steinach, E., Zentralbl. f. Physiol., 1910, xxiv., 551; Arch. f. d. ges. Physiol., 1912, cxliv., 72.

200 For the literature on the subject the reader is referred to Morgan, T. H., Sturtevant, A. H., Muller, H. J., and Bridges, C. B., The Mechanism of Mendelian Heredity. New York, 1915.

201 Mendel, G., “Experiment in Plant-Hybridiza­tion,” translated in W. Bateson’s classical book on Mendel’s Principles of Heredity. Cambridge, 1909.

202 The reader will find a critical discussion of the presence and absence theory on page 220 of Morgan, Sturtevant, Muller, and Bridges, The Mechanism of Mendelian Heredity. New York, 1915.

203 Sutton, W. S., “The Chromosomes in Heredity,” Biol. Bull., 1904, iv., 231.

204 Morgan, T. H., Sturtevant, A. H., Muller, H. J., and Bridges, C. B., Mechanism of Mendelian Heredity. New York, 1915, p. 26.

205 Morgan, T. H., Sturtevant, A. H., Muller, H. J., and Bridges, C. B., The Mechanism of Mendelian Heredity. New York, 1915.

206 Bateson, W., loc. cit., p. 157.

207 The number of hereditary characters examined to test the theory was over 130.

208 Bateson, W., Mendel’s Principles of Heredity, 3d ed., 1913; Davenport, Chas. B., Heredity in Rela­tion to Eugenics, 1911. Pearl, R., Modes of Research in Genetics.

209 Loeb, J., King, W. O. R., and Moore, A. R., Arch. f. Entwcklngsmech., 1910, xxix., 354. These experi­ments have been repeated at different seasons of the year and in different years and have been found to be constant.

210 Moore, A. R., Arch. f. Entwcklngsmech., 1912, xxxiv., 168.

211 Bertrand, G., Ann. d. l’Inst. Pasteur, 1908, xxii., 381; Bull. Soc. Chim., 1896, xv., 791.

212 Chodat, R., Arch. d. Sc. phys. et nat., 1915, xxxix., 327.

213 Gortner, R. A., Trans. Chem. Soc., 1910, xcvii., 110.

214 Onslow, H., Proc. Roy. Soc., 1915, B. lxxxix., 36.

215 Loeb, J., “Egg Structure and the Heredity of Instincts,” The Monist, 1897, vii., 481.

216 Bateson, W., Nature, 1916, xciii., 674.

217 Ideas similar to those expressed in this chapter may be found in the writer’s former book Comparative Physiology of the Brain and Comparative Psychology, New York, 1900, and in the books by George Bohn, La Naissance de l’Intelligence, Paris, 1909, and La nouvelle Psychologie animale, Paris, 1911.

218 Graber, V., Grundlinien zur Erforschung des Helligkeits- und Farbensinnes der Tiere. Prag, 1884.

219 Loeb, J., Sitzungsber. d. physik.-med. Gesellsch. Würzburg, 1888. Der Heliotropismus der Tiere und seine Übereinstimmung mit dem Heliotropismus der Pflanzen. Würzburg, 1889. Arch. f. d. ges. Physiol., 1897, lxvi., 439.

220 Loeb, J., Arch. f. d. ges. Physiol., 1890, xlvii., 391; 1896, lxiii., 273.

221 Loeb, J., Arch. f. d. ges. Physiol., 1897, lxvi., 439.

222 Loeb, J., The Mechanistic Concep­tion of Life, Chicago, 1912, p. 27.

223 Loeb, J., and Ewald, W. F., Zentralbl. f. Physiol., 1914, xxvii., 1165.

224 Ewald, W. F., Science, 1913, xxxviii., 236.

225 Fröschel, P., Sitzungsber. d. k. Akad. d. Wissensch., Wien, 1908, cxvii.

226 Blaauw, H. A., Rec. d. travaux botaniques Neérlandais, 1909, v., 209.

227 Loeb, J., Arch. f. d. ges. Physiol., 1893, liv., 81; Jour. Exper. Zoöl., 1907, iv., 151.

228 Bancroft, F. W., Jour. Exper. Zoöl., 1913, xv., 383.

229 Loeb, J., Studies in General Physiology, Chicago, 1905, p. 2.

230 Patten, Bradley M., Am. Jour. Physiol., 1915, xxxviii., 313.

231 According to this theory the animal is not directly oriented by the outside force, e. g. the light, but selects among its random movements the one which is most “suited” and keeps on moving in this direc­tion. This idea is untenable for most if not all the cases of tropisms and has been refuted by practically all the workers in this field, e. g., Parker and his pupils, Bohn, H. B. Torrey, Holmes, Bancroft, Ewald, and others. It is only upheld by Jennings and Mast; and is accepted among those to whom the idea of a physico­chemical explana­tion of life phenomena does not appeal. Torrey and Bancroft (for the literature the reader is referred to Bancroft’s paper, Jour. Exper. Zoöl., 1913, xv., 383) have shown directly that the theory of trial and error is not even correct for the organism for which Jennings has developed this idea; namely Euglena.

232 Loeb, J., and Maxwell, S. S., Arch. f. d. ges. Physiol., 1896, lxiii., 121.

233 That the mechanisms by which helio­tropic and galvano­tropic orienta­tion is brought about are identical was shown by Bancroft in Euglena (Bancroft, loc. cit.).

234 Loeb, J., and Maxwell, S. S., Arch. f. d. ges. Physiol., 1896, lxiii., 121.

235 Loeb, J., Dynamics of Living Matter, p. 126.

236 Loeb, J., and Maxwell, S. S., Univ. Cal. Pub., 1910, Physiol., iii., 195; Loeb and Wasteneys, Proc. Nat. Acad. Sc., 1915, i., 44; Science, 1915, xli., 328; Jour. Exper. Zoöl., 1915, xix., 23; 1916, xx., 217.

237 Mast, S. O., Proc. Nat. Acad. Sc., 1915, i., 622.

238 Hess, C., “Gesichtssinn,” Winterstein’s Handb. d. vergl. Physiol., 1913, iv.

239 v. Frisch, K., “Der Farbensinn und Formensinn der Biene,” Zoöl. Jahrb. Abt. f. allg. Zoöl. u. Physiol., 1914, xxxv. See also Ewald, W. F., Ztschr. f. Sinnesphysiol., 1914, xlviii., 285.

240 Loeb, J., Der Heliotropismus der Tiere, 1889.

241 Kellogg, V. L., Science, 1903, xviii., 693.

242 Loeb, J., Arch. f. d. ges. Physiol., 1906, cxv., 564.

243 Ibid., 1893, liv., 81.

244 Groom, Theo. T., and Loeb, J., Biol. Centralbl., 1890, x., 160; Ewald, W. F., Jour. Exper. Zoöl., 1912, xiii., 591.

245 Loeb, J., Arch. f. d. ges. Physiol., 1906, cxv., 564; Moore, A. R., Jour. Exper. Zoöl., 1912, xiii., 573.

246 Cannon, W. B., Bodily Changes in Pain, Hunger, Fear, and Rage, New York, 1915.

247 Setchell, W. A., Science, 1903, xxvii., 934.

248 Duclaux, E., Traité de microbiol., 1898, i., 280.

249 A full discussion of the literature on temperature coefficients is given in A. Kanitz’s book on Temperatur and Lebensvorgänge, Berlin, 1915.

250 Van Slyke, D. D., and Cullen, G. E., Jour. Biol. Chem., 1914, xix., 141.

251 These considera­tions may meet the objec­tions of Krogh to the applica­tion of the van’t Hoff rule of temperature effect on reac­tion velocity to life phenomena. See also the discussion of this subject in Kanitz’s book.

252 Lillie, F. R., and Knowlton, E. P., Zoöl. Bull., 1897, i.

253 Hertwig, O., Arch. mikrosk. Anat., 1898, li., 319. See also E. Cohen, Vorträge für Aerste über physikalische Chemie. 2d ed. Leipzig, 1907.

254 Loeb, J., Arch. f. d. ges. Physiol., 1908, cxxiv., 411; Loeb J., and Wasteneys, H., Biochem. Ztschr., 1911, xxxvi., 345; Loeb J., and Chamberlain, M. M., Jour. Exper. Zoöl., 1915, xix., 559.

255 Loc. cit.

256 Kanitz, A., loc. cit., p. 123.

257 Loeb, J., and Chamberlain, M. M., Jour. Exper. Zoöl., 1915, xix., 559.

258 Loeb, J., and Ewald, W. F., Biochem. Ztschr., 1913, lviii., 179.

259 Clausen, H., Landwirtschaftl. Jahrb., 1890, xix., 893.

260 Matthaei, G. L. C., Trans. Philosoph. Soc., 1904, cxcvii., 47; Blackman, F. F., Ann. of Bot., 1905, xix., 281.

261 Loeb, J., “The Poisonous Character of a Pure NaCl Solu­tion.” Am. Jour. Physiol., 1900, iii., 329; Arch. f. d. ges. Physiol., 1901, lxxxviii., 68; Am. Jour. Physiol., 1902, vi., 411; Biochem. Zischr., 1906, ii., 81.

262 Loeb, J., Jour. Biol. Chem., 1915, xxiii., 423.

263 Loeb, J., “On the Physiological Effects of the Valency and Possibly the Electrical Charges of Ions,” Am. Jour. Physiol., 1902, vi., 411.

264 Loeb, J., Jour. Biol. Chem., 1914, xix., 431.

265 Loeb, J., Arch. f. d. ges. Physiol., 1905, cvii., 252.

266 Robertson, T. B., Ergeb. d. Physiol., 1910, x., 216.

267 Loeb, J., Biochem. Ztschr., 1912, xlvii., 127.

268 Osterhout, W. J. V., Bot. Gazette, 1906, xlii., 127; 1907, xliv., 257; Jour. Biol., Chem., 1906, i., 363.

269 Ostwald, Wo., Arch. f. d. ges. Physiol., 1905, cvi., 568.

270 Loeb, J., Jour. Biol. Chem., 1915, xxiii., 423.

271 Loeb, J., Jour. Biol. Chem., 1905–06, i., 427.

272 Meltzer, S. J., and Auer, J., Am. Jour. Physiol., 1908, xxi., 400.

273 This theory was first expressed by the writer in Am. Jour. Physiol., 1900, iii., 434.

274 Henderson, L., The Fitness of the Environment. See also Michaelis, L., Die Wasserstoffionenconzentra­tion. Berlin. 1914.

275 Loeb, J., Der Heliotropismus der Tiere and seine Übereinstimmung mit dem Heliotropismus der Pflanzen. Würzburg, 1890 (appeared in 1889).

276 Loeb, J., Biol. Bull., 1915, xxix., 50.

277 Cuénot has proposed the term preadapta­tion for such cases and this term expresses the situa­tion correctly. Cuénot, L., La Génèse des Espèces animales. Paris, 1911.

278 Kammerer, P., Arch. f. Entwcklngsmech., 1912, xxxiii., 349.

279 Loeb, J., Arch. d. f. ges. Physiol., 1896, lxiii., 273.

280 Goldfarb, A. J., Jour. Exper. Zoöl., 1906, iii., 129; 1910, viii., 133.

281 Loeb, J., Biochem. Ztschr., 1913, liii., 391.

282 Loeb, J., Biochem. Ztschr., 1913, liii., 391.

283 Dieudonné, A., Arb. a. d. kais. Gesndhtsmt., 1894, ix., 492.

284 Davenport, C. B., and Castle, W. E., Arch. f. Entwcklngsmech., 1896, ii., 227.

285 Kryž, F., Arch. f. Entwcklngsmech., 1907, xxiii., 560.

286 Loeb, J., and Wasteneys, H., Jour. Exper. Zoöl., 1912, xii., 543.

287 Kammerer, P., Arch. f. Entwcklngsmech., 1909, xxviii., 448.

288 Bateson, W., Problems of Genetics, pp. 201–202. Yale University Press, 1913.

289 Kammerer, P., Arch. f. Entwcklngsmech., 1913, xxxvi., 4.

290 Werner, F., Biol. Centralbl., 1915, xxxv., 176.

291 Loeb, J., The Mechanistic Concep­tion of Life. Chicago, 1912.

292 de Vries, H., The Muta­tion Theory, translated by Farmer, J. B., and Darbishire, A. D., Chicago, 1909. Species and Varieties. Chicago, 1906. Gruppenweise Artbildung. Berlin, 1913.

293 For a critical discussion of the details, see Bateson, W., Problems of Genetics, New Haven, 1913, Chapter X.

294 Fermi, C., Centralbl. f. Bacteriologie, Abt. 1, 1910, lvi., 55.

295 Levene, P. A., Autolysis. The Harvey Lectures, 1905–1906, p. 73, gives a full account of the work on this subject up to 1905.

296 Hoppe-Seyler, F., Tübinger med.-chem. Untersuchungen, 1871, P. 499.

297 Levene, P. A., Am. Jour. Physiol., 1904, xii., 276.

298 Bradley, H. C., and Morse, M., Jour. Biol. Chem., 1915, xxi., 209.

299 Bradley, H. C., ibid., 1915, xxii., 113.

300 Loeb, J., Arch. f. d. ges. Physiol., 1895, lxii., 249.

301 Budgett, S. P., Am. Jour. Physiol., 1898, i., 210.

302 Loeb, J., The Dynamics of Living Matter, New York, 1906, pp. 19–21.

303 Child, C. M., Senescence and Rejuvenescence, Chicago, 1915.

304 It is a fact that in the early cells of Ctenolabrus the dissolu­tion of the cell walls through lack of O precedes death, since when oxygen is admitted early enough the cells recover again. In infusorians the bursting of the animal due to lack of O occurs suddenly, while the animal is still moving, and this bursting is the cause of death, and not the reverse.

305 Metchnikoff, E., Ann. d. l’Inst. Pasteur, 1915, xxix., 477.

306 Loeb, J., Biol. Bull., 1902, iii., 295.

307 Loeb, J., Arch. f. d. ges. Physiol., 1908, cxxiv., 411.

308 K. Brandt (“Über den Nitratgehalt des Ozeanwassers and seine biologische Bedeutung,” Abh. d. kais. Leop. Carol. deutsch. Akad. d. Naturfoscher., 1915) accounts for this fact by the assump­tion that through the greater activity of the denitrifying bacteria in the tropical waters the amount of available nitrates is here comparatively smaller than in the polar oceans. The writer fully appreciates the importance of this fact but nevertheless is inclined also to see a limiting factor in the enormously rapid decline of the dura­tion of life at the upper temperature limits.

309 Metchnikoff, E., The Prolonga­tion of Life. New York, 1907.