THE PHYSIOLOGY OF CELL DIVISION 



35 



In this series the alcohols, with the exception of propyl alco- 

 hol, showed well-marked though not pronounced action. The 

 concentrations in which the alcohols act most favorably corre- 

 spond closely with the minimal concentrations for producing mus- 

 cular anesthesia in Arenicola larvae." The above solutions of 

 propyl and butyl alcohols appear to be somewhat above the op- 

 timal strength; in most of the following experiments weaker so- 

 lutions, 2 V. per cent and 0.8 v. per cent respectively, were used. 

 The following series (table 3) shows results similar to the above. 



TABLE 3 

 July 27: The treatment was the same as in the preceding series 



AFTE R-TKE ATM ENT 



PROPOeTION OP EGGS FORMING LARVAE 



1. None (treated with 0.55m NaCl 

 alone) 



2. Hypertonic sea-water 



3. Sea-water + m/lOOO KCN 



4. Sea-water + 5 v. % ethyl alcohol 



5. Sea-water -(- 2 v. % n-propyl alcohol 



6. Sea-water + 0.8 v. % n-butyl alcohol 



7. Sea-water + 0.25 v. % n-amyl alcohol 



Very few form larvae : < 1 % 



Well-marked increase: 10-15 % 

 Marked increase: 40-50 % 

 Marked increase: 20-25 % 

 Marked increase: 30-40 % 

 Less favorable: 15-20 % 

 Still less favorable: 5-10 % 



Controls. Nearly all eggs fertilized one hour after removal develop normally. 

 Unfertilized eggs undergo normal coagulation without membrane-formation or 

 cleavage. 



In the experiments with sodium chloride solution, followed 

 by after-treatment as above, the proportion of eggs developing 

 to a larval stage was in some cases considerable — at times reach- 

 ing 30 or 40 per cent — but never very high. In several other 

 similar experiments less favorable results were obtained; usually 

 the after-treatment caused a definite increase in larvae, but ex- 

 ceptions to this rule sometimes occurred, especially when the eggs 

 were in any way abnormal. As already mentioned, sodium chlo- 

 ride solution gives in general less favorable results than the other 

 two membrane-forming agents, probably because the action of 

 the salt is too energetic and tends to produce effects not readily 

 reversible by the subsequent action of the anesthetic, hypertonic 

 sea-water, or cyanide. The experiments with fatty acid about 



^' American Journal of Physiology, 1913, vol. 31, p. 264. 



