226 L. V. HEILBRUNN 



centrifuged, the handle being turned 50 times in 30 seconds. The D 

 eggs had a hyaUne zone extending one-third or more of the distance 

 along the stratification axis. In these eggs the gray cap was appar- 

 ently lacking. In the control normal eggs the original gelation was 

 beginning its normal reversal, and the hyaUne zone extended about 

 one-fourth of the stratification axis. At 12:23| p.m. eggs in C and nor- 

 mal eggs were centrifuged simultaneously, the handle being turned 50 

 times in 30 seconds. Of the C eggs almost all were cytolyzed and 

 showed no stratification. A few, however, showed a hyaline zone one- 

 half to two-thirds of the distance along the axis of stratification. Such 

 a marked liquefaction is often the preliminary of coagulation. In the 

 normal eggs at this time, segmentation was beginning, and the hyaline 

 zone was poorly shown. 



The eggs inA,B, C, D, did not segment. Those in E had numerous 

 small cells cut off from the margin. This is an appearance typically 

 found in all cases where the concentration of the anesthetic is not quite 

 sufficient to stop segmentation completely. In F, the cleavage was 

 much more nearly normal. These observations were made at about 

 1:30 P.M. At 12:36 to 12:37 p.m. some eggs from each of the dishes A 

 to F had been transferred to Stender dishes contaming fresh sea-water. 

 Those from A were put into a, those from B into b, etc. These dishes 

 were then examined at 1:45 p.m. No segmentation occurred in a, b, 

 c, and in d only abnormal evidences of the segmentation process were 

 found. But in e and / normal segmentation occurred, and motile 

 blastulae were later found in these dishes. 



July 24th. Acetonitrile {methyl cyanide). At 11:35| a.m. eggs were 

 fertilized. Ten minutes later they were placed in vials containing solu- 

 tions of acetonitrile in sea-water. Vial A contained 5 per cent, B 4 

 per cent, C 2| per cent, D 2 per cent, E 1 per cent, F | per cent, G \ 

 per cent. At 11:52 a.m., eggs in B and normal eggs were centrifuged 

 simultaneously the handle being turned 50 times in 28 seconds. The 

 B eggs had a hyaline zone one-third to one-half the extent of the egg 

 axis, whereas the normal controls showed barely a trace of hyaline zone 

 in a few cases. At 11:59 a.m., eggs in A and normal eggs were centri- 

 fuged at the same speed as in the previous test. A few of the A eggs 

 showed a hyaline zone extending along one-third of the egg axis, but in 

 most cases the eggs were coagulated and showed no stratification. 

 The control of normal eggs exhibited no stratification, except in a few 

 cases which showed trace of a hyaline zone. 



At 12:05 to 12:07| p.m. some eggs were transferred out of A, B, C, 

 D, E, F, G, into normal sea-water in Stender dishes a, b, c, d, e, /, g, 

 respectively. At 2:15 to 2:30 p.m. eggs in A to G and a to g were ex- 

 amined. In A and B, no segmentation of any kind had occurred. In 

 C and D, there was no normal segmentation, but in many of the eggs 

 small cell-like masses had apparently been cut off from the cell periph- 

 ery. In E, 10 per cent of the eggs had segmented in more or less 

 normal fashion, others had segmented abnormally. In F and G, nor- 

 mal segmentation had occurred generally. In a, 20 per cent of the 



