384 WILSON GEE. 



(d) Effects of Treatment on Cleavage. The "percentage de- 

 veloping beyond early cleavages" as applied in these results is a 

 term which does not indicate the percentage of fertilizations 

 except in the control. Here there are very few of the aberrant 

 cleavages, though occasionally one does occur. However, in 

 practically every series of eggs treated with two per cent, or five 

 per cent, alcohol there occur some four or five hours after fertailiz- 

 tion a number of aberrant cleavages. In some instances there 

 may be as many as twenty or thirty of these in a single lot of 

 eggs ; in others only a very few. 



The number of eggs developing in each lot treated is so small 

 that it was rather difficult to follow the rate of cleavage as com- 

 pared with the control. In the treated lot there were usually 

 to be observed at the time of the first cleavage in the control a 

 few in a similar stage. As will be noted from the legend accom- 

 panying the figures (see Figs. 1-9), the aberrant cleavages of the 

 types figured in the text represent delayed cleavages in almost 

 every instance. 



In three series of experiments, all of these aberrant cleavages 

 were removed to a separate dish. Upon examination several 

 hours later the blastodiscs of the most of them were found to 

 have disintegrated and to resemble the condition of the eggs 

 that had not been fertilized at all. Frequently two or three out 

 of some eighteen or twenty continued to develop at a slow rate, 

 producing in most instances defective individuals or those of 

 low vigor. 



Sections were cut of several of these irregular cleavages, but 

 aside from the fact that fragmented nuclear material of some 

 sort seems to be present, the time available has prevented a 

 fuller analysis. The cleavage planes are not deeply cut into the 

 cytoplasm of the blastodisc, but are superficial in extent. It 

 may be that the effect of the alcohol upon the egg nucleus is 

 such that it causes fragmentation, followed by various degrees of 

 rounding up of the adjacent cytoplasm. Other possibilities 

 suggest themselves. The nature of these cleavages seems to 

 afford an interesting problem, and one of which the waiter hopes 

 to make a closer study at some later date. 



(e) Effects on Percentage Developing Sub-normally. In these 



