358 



Dr. H. M. Vernon. The Effect of Stateness of the 



The next experiment in the table is not so satisfactory, as in the one 

 instance in which stale $ stale ft larvae were obtained, there was 

 a distinct diminution in size ; whilst in one of the two sets of fresh $ 

 stale ft larvae, there was also a diminution, instead of the expected 

 increase. In the two experiments with stale ova and fresh sperm, the 

 diminution was in each case very considerable, so that the somewhat 

 abnormal results obtained in this series of experiments may perhaps be 

 put down to the fact that all the larvae, whatever the conditions under 

 which they were obtained, showed a tendency to undergo diminution in 

 size. 



In all the experiments thus far described, the fresh normal larvae 

 were measured as well as the original normal larvae. In another series 

 of observations, however, and in all the observations described in the 

 former paper, only the original normal larvae were measured ; hence, 

 though the values obtained for stale $ stale ft larvae are just as accu- 

 rate as before, those for stale $ fresh ft and fresh $ stale ft larvae 

 are presumably less accurate, as they are also compared against the 

 original normal larvae, and not the mean of the original and fresh 

 larvae. All these observations are collected in the subjoined table. In 



Condition of sexual 

 cells. 



Fertilisation made after 



Means of 



all 

 observa- 

 tions. 



24 hrs. 



18 hrs. 



9 hrs. 



22 hrs. 



9 hrs. 



Fresh $ , stale $ . . . . 

 Stale %, fresh $ 



-1-8 

 + 5-5 

 -0-4 



+ 11-0 

 -17-6 



+ 9-6 



+ 2'0 

 + 3'5 

 -11-3 



-3-4 

 -9-5 

 -1-8 



-0 74 

 + 4-05 

 -6-90 



Body length of normal 



30 '22 



30 -72 



29-41 





30-95 





the first series, the one not recorded in the former paper, there is a. 

 slight diminution in the size of the stale $ stale ft larvae, but a con- 

 siderable increase in that of the fresh $ stale ft larvae. In the next 

 experiment no stale $ stale ft larvae were obtained, but the fresh $ 

 stale ft larvae showed a very marked increase in size, and the stale $ 

 fresh ft larvae showed the maximum decrease of 17*6 per cent. Most 

 of the rest of the observations conform more or less to the rule above 

 laid down, but there is one very marked exception, the fresh $ stale ft 

 larvae being in one case 9*5 per cent, smaller than the normal, instead 

 of larger, as one would expect. 



Taking means of all the observations in both series, we find that as. 

 an average of eight observations, the stale $ stale ft larvae were 

 diminished 0*7 per cent, in size ; as an average of eleven observations, 

 the fresh ? stale ft larvae were increased 4 per cent., and as an average; 



