244 NEIL S. DUNGAY. 



two cases of such figures in eggs with but one polar body have 

 been noted in late cleavage stages. Other eggs may fail entirely 

 to produce polar bodies. In these eggs from six to nine poles 

 form and the spindles are often very complicated and produce 

 an irregular distribution of the chromosomes, which, in the 

 earlier figures, take the form which is found on the second 

 maturation spindles. It has been shown (Lillie, F. R., 'n) 

 that the formation of the first polar body may be prevented by 

 the use of the centrifuge. In such cases multipolar figures of 

 various kinds are formed. Clearly my case is due to the sup- 

 pression of the polar bodies. I have not seen similar cases in 

 sections of normal series though, in such small numbers as are 

 found in the experimental series, it is possible that they may 

 have been overlooked. 



(b 4) A few scattering abnormalities have also been found but 

 not in sufficient numbers to be of any significance. Two cases 

 in which the sperm and egg nuclei fused together and failed to 

 develop farther have been seen. Two cases of prophase figures 

 from second cleavage were found in which the spindles lay at 

 right angles to each other in different planes. Other abnormal 

 conditions were also found. All of these cases are open to the 

 interpretation that the egg was abnormal before fertilization 

 and are not worth description. 



Careful search was made for eggs showing abnormalities at 

 the period of entrance of the sperm. It seemed likely that the 

 stages of fusion of the egg and sperm nuclei would contain evi- 

 dence of abnormality but close examination failed to show 

 anything of the kind, except in the case of the two eggs already 

 mentioned. Since a kind of parthenogenetic cleavage might be 

 produced by the partial action of the sperm cell, search was made 

 for eggs exhibiting the haploid number of chromosomes in the 

 first cleavage. But in all cases the number was clearly diploid. 



VI. DISCUSSION. 



A. The Production of Defectives. For a long time it has been 

 assumed by many that the offspring of parents who habitually 

 take alcohol or other drugs or who work in lead are very apt to 

 be in some way weak or defective. Some of the unfortunate 



