278 MR. NEWPORT ON THE IMPREGNATION OF THE OVUM IN THE AMPHIBIA 



Twenty minutes after narcotization, and during which time not a single sperma- 

 tozoon had been observed in motion, a portion of them were applied in the same way as 

 above to three other eggs, but not one of these became fecundated, no chamber being 

 formed within them, and no embryo was produced. Many of the spermatozoa at this 

 time were dead, as was shown by the looping of their bodies, but there was still a 

 quantity which had been simply narcotized and lay extended at length. 



One hour after narcotization another portion was applied to two eggs, one of which 

 became partially fecundated. The chamber appeared in it above the yelk, the yelk 

 underwent segmentation, and afterwards an embryo was begun to be formed, but its 

 development was not completed, and the egg then perished. The second was not 

 fecundated. The circumstance of this egg having been fertilized at so long a period 

 after the fluid had been narcotized, leads to the conclusion that impregnation had 

 been effected by revived spermatozoa. 



On the following day I repeated these experiments with very mature fluid imme- 

 diately after it was obtained, and in which the spermatozoa were exceedingly vigorous. 

 One minute and a half after it had been exposed to chloroform, I found that the same 

 effect had been produced on the spermatozoa as that which is produced in them by 

 their admixture with very weak solution of potass ; their power of motion was 

 greatly increased, and the whole were in a state of intense action. After a few 

 minutes' longer exposure their motion was perceptibly diminished, and at the end of 

 about ten minutes it had almost entirely ceased, as only a few of them were then 

 observed to move. 



Three eggs were supplied, by means of the pin's head, with these narcotized sper- 

 matozoa. The respiratory chamber was formed in two of these eggs, and one of 

 them underwent segmentation, and at the end of the fifth day an embryo had begun 

 to be produced, but its development did not proceed, and this egg like the other 

 two perished. 



Six eggs were then supplied copiously by means of the loaded pin's head, three 

 times applied to each, nearly the whole of the spermatozoa employed being then mo- 

 tionless, and having already remained so for about ten minutes, only an occasional 

 one being observed in feeble action. Two of these eggs became partially impreg- 

 nated, the usual chamber being formed in them, but neither of them underwent seg- 

 mentation, nor was any embryo formed either in these or the others. 



Three eggs were then supplied as above after the spermatozoa had been motionless 

 during twenty minutes, not one being observed with the slightest action at the time 

 of the experiment. No chamber was formed in either of these, but the whole 

 remained unimpregnated. 



Three eggs were the subject of further trial, when the spermatozoa employed had 

 been motionless during half an hour. At this time one or two spermatozoa were 

 again observed to be in feeble action, but no impregnation was effected. 



Thirteen eggs were employed when the spermatozoa had remained motionless 



