THE PHYSIOLOGY OF CELL DIVISION 



37 



days later. The table gives a summarized account of the results 

 of all six series. 



The results of these experiments show considerable uniformity. 

 The number of larvae resulting from acid treatment alone was 

 small, and each form of after-treatment caused a decided in- 

 crease in the proportion of eggs forming larvae. It is noteworthy 

 that hypertonic sea-water is on the whole less favorable than the 

 other solutions. Cyanide and chloral hydrate show somewhat 

 better results than the other solutions ; this, however, is not always 

 the case, as the following experiments with alcohols will illustrate. 



TABLE 4 



In each series the eggs were exposed, about one hour after removal from the animals, 

 to a solution containing 6 cc. n/lO acetic acid, plus 100 cc. sea-water, for one to 

 two minutes. Ten minutes later they were brought into the several solutions of 

 the series, where they remained for thirty minutes; they loere then returned to sea- 

 water. Part of the acid-treated eggs received no after-treatment {for control). 

 The hypertonic sea-water consisted in all cases of a mixture of 250 cc. sea-water 

 plus 30 cc. 2.5m NaCl. The solutions (in sea-water) of cyanide and anaesthetics 

 were kept in corked flasks. The results are given in approximate percentages of 

 mature eggs forming swimming larvae (blastulae or gastrulae), under the date of 

 the experiment. The condition of the control eggs, sperm-fertilized and unfer- 

 tilized, i^ recorded in each case. 



