314 E. M. NELSON ON THE HUMAN SPERMATOZOON. 



and the diameter of the two nucleoli pins the interspace was 

 — - — inch. As the nucleoli were of equal size it follows that 



3 2 J- 



the diameter of the nucleolus could not be greater than 64000 ; 

 therefore, assuming that the interspace between the nucleoli 

 was j of the diameter of the nucleolus, it follows that the 

 interspace was 757V00 inch, or -0997/x. 



It is quite impossible to say what is the thickness of the 

 filament ; it appears to be thicker than the flagella of the smallest 

 bacteria, but not so thick as those of the larger forms. It is 

 much finer than the barb on the spermatozoon of the newt 

 which I discovered and exhibited here in 1882. 



In the human spermatozoon I have seen as many as four 

 nuclei in one spore. I have also observed many abnormal 

 specimens, such as two heads on one tail ; two tails on one 

 head ; two heads and two tails joined together like Siamese 

 twins. 



The following are measurements of an average spermato- 

 zoon : — 



Head (spore and cup) long.., 



broad.. 



Stem Ions' 



o 



4 2 5 

 1 



7500 

 1 



5 700 



600 



1 



5'V 

 3-4/x. 



4'4^u. 



•05mm. 



•06mm. 



Tail (joint to lip) 



Total (head, stem, and tail).. 

 Thus it will be seen that the spore and cup are ^ of the 

 total length of the spermatozoon. In conclusion I must plead 

 my total inability to represent anything by freehand drawing, 

 for the very indifferent picture I place before you. I trust, 

 however, that with the assistance of the description, a more 

 correct idea of this interesting object will be presented to 

 your minds than that which has obtained hitherto. 



