EFFECTS OF INJURY UPON SPERM. 235 



stages from blastula to pluteus before any considerable number 

 of deaths were observed in the controls. A very small number 

 died during cleavage in stages beginning with the undivided egg. 

 Blastulse whose cavities were more or less filled with cells, similar 

 to the stereoblastulse so often described by experimental workers, 

 were found in increasingly large percentages as the strength or 

 duration of the injurious agent acting upon the sperm was in- 

 creased. In some cases over 15 per cent, of the experimental 

 cultures were of this form. They did not appear to develop 

 farther but went to pieces. Evaginate gastrulse were formed 

 rather uniformly throughout the experimental series and occa- 

 sionally one or two were found in the controls. The proportion 

 of this type of abnormality did not seem to show so close a corre- 

 lation with the degree of injury to the sperm as did the stereo- 

 blastulse. Other types of abnormal gastrulae were very common, 

 this stage seeming to be a difficult one to pass. Some were 

 observed to be much smaller in size than the normal type, perhaps 

 due to a separation of the blastomeres in the early stages. Others 

 were irregular in various ways. The most common type of this 

 irregularity is what I have called in my notes "ragged." These 

 forms do not possess such a clean cut appearance but are cpvered 

 with minute irregularities and look as though they were going 

 bad. The plutei were variable in the controls, but they were very 

 much more so in the experimental cultures. The arms sometimes 

 failed to form or appeared only as small buds. Usually however 

 the arms were longer and more slender than in the controls. 

 Several cases were observed in which the anal opening did not 

 form. In all cases after the first appearance of motility a much 

 larger number was found in the experimental cultures lying 

 motionless on the bottom of the dish. If disturbed they quickly 

 settled down to their former condition of rest. Some seemed to 

 entirely lack the power of motion although this was not certainly 

 determined. 



In general all of the results point toward a great disturbance 

 in the development of all or nearly all parts of the organism. 

 This disturbance seems to be produced by injury to the sperm 

 cells used in insemination. An attempt to see if, in the case of 

 the experiments using alcohol, the disturbance was due to a 



