RALPH S. LILLIE. 



in the metabolic sequence conditioning development. This is 

 suggested not only by the fact that autolysis typically leads to 

 structural breakdown and cytolysis, but also and more especially 

 by its being characteristically furthered by many of the general 

 cytolytic and parthenogenetic agents, such as lipoid-solvents, 

 acids and high temperatures. Ether, chloroform and alcohol 

 greatly accelerate the autolysis of liver-cells and shorten the 

 latent period of the process; 1 and acids, including COa, are well 

 known to have the same effect. 2 Chiari attributes the effect of 

 lipoid-solvents to an increase of protoplasmic permeability, 

 allowing readier diffusion of enzymes and the other substances 

 concerned. There is also evidence that autolytic processes 

 underlie various structural and other physiological changes, some 

 of which are of a kind frequently met with in development, e. g., 

 atrophic changes 3 (to which are related normal regressive proc- 

 esses like the involution of the uterus and the resorption of 



1 Chiari, Arch.f. exper. Path. u. Pharm., 1908, Vol. 60, p. 256; cf. also Yoshimoto, 

 Zeitschr. f. physiol. Chem., igoS, Vol. 58, p. 341. 



- Cf. Hedin and Rowland, Zeitschr. f. physiol. Chem., 1901, Vol. 32, p. 241; 

 Schryver, Biochemical Journal, 1906, Vol. i, p. 123; Arinkin, Zeitschr. f. physiol. 

 Chem., 1907, Vol. 53, p. 192; Bellazi, ibid., 1908, Vol. 57, p. 389; Yoshimoto, ibid., 

 1908, Vol. 58, p. 341; Bradley, cf. footnote page 153. Bellazi and Yoshimoto describe 

 experiments with CC>2. Cf. also Lacqueur, Zeitschr. f. physiol. Chem., 1912, 'Vol. 

 79, p. 82; Lacqueur finds that carbon dioxide promotes and oxygen checks the 

 autolysis of liver-cells. According to Lyon and Shackell (Journal of Biological 

 Chemistry, 1909, Vol. 7, p. 371) acetic acid promotes the autolysis of sea-urchin eggs. 



It should be noted that in the activation of eggs by acid the visible effects of 

 the treatment do not appear at once, but only after the eggs have been returned 

 to normal sea- water; this shows that for the initiation of the membrane-forming 

 process time is required, representing possibly the latent period of the enzyme 

 action. Hedin's observation that a temporary treatment of various tissues with 

 acetic acid greatly increases the subsequent rate of autolysis i. e., the autolysis 

 is decidedly more rapid in previously treated than in untreated portions of tissue 

 under otherwise similar conditions, and even in presence of alkali may have a 

 bearing here (Cf. Hedin, Festkrift O. Hammarsten, Upsala, 1906; also Rhodin, 

 Zeitschr. f. physiol. Chem., 1911, Vol. 75, p. 197). Hedin ascribes this result to the 

 destruction of an inhibitory substance by the acid. This suggests the possibility 

 that in the activation of eggs by acid the deciding factor may be the destruction 

 of an antibody (anti-protease?) in the egg-cortex; an activation so induced would 

 be irreversible (as seems in fact to be the case). This view, however, does not seem 

 consistent with the observed relations between concentration of acid and time of 

 action, as described above (see footnote on page 132). The question as to the precise 

 conditions of acid-activation is evidently an open one. 



3 Cf. Jacoby, Zeitschr. f. physiol. Chem., 1900, Vol. 30, p. 174. 



