246 



Scientific Proceedings (129) 



rapid growth. 5 It is thus clear that this quantity of insulin 

 blocks ovulation both by preventing ova from beginning their 

 final period of rapid growth and by sometimes causing them to 

 be resorbed after having entered this stage of growth. 



The data (sugar curve for 10 birds) of the accompanying 

 paper 6 show that in the suppressed ovulations of our table 1 

 the blood sugar was lowered to about .080 per cent. — or one- 

 half its normal value — for a period not longer than four hours 

 twice daily. Depression of the blood sugar to this extent is 

 sufficient to suppress many or most ovulations in ring doves. 



In making the necessary tests for the proper dosage for the 

 above purpose it was further learned that the pigeon shows a 

 marked resistance to the lethal action of the extract. This fact 



TABLE II. 



The resistance of doves and pigeons to large subcutaneous doses of insulin. 

 Birds not permitted to eat until 48 hours after injection. 

 (Upper part of table = ring doves; lower — common pigeons). 



No. 



Amount 



of iletin. 



Time 









(hours) 





of 





X lethal 



no food 



Death or survival and remarks. 



bird. 



Units. 



for 



before 









rabbit. 



injection 





1 



5.0 



33 



21 



Died after 5 days; took no food. 



o 



4.5 



30 



22 



Survived. 



3 



4.8 



30 



7 



Survived. 



4 



4.7 



30 



7 



Died* after 28-34 hours. 



5 



5.0 



30 



22 



Survived. 



6 



5.0 



30 



22 



Survived. 



7 



3.2 



20 



5 



Survived. 



8 



1.3 



10 



21 



Died* after 36-42 hours. 



9 



1.7 



10 



0 



Survived. 



10 



1.8 



10 



0 



Survived. 



11 



1.5 



10 



0 



Survived. 



12 



1.5 



10 



0 



Survived. 



13 



1.0 



6 



0 



Survived. 



14 



1.0 



6 



0 



Survived. 



15 



1.0 



6 



0 



Survived. 



16 



10.5 



33 



0 



Died after 8.5 hours.* 



17 



5.8 



18 



22 



Survived. 



18 



5.7 



18 



20 



Survived. 



19 



3.5 



10 



22 



Survived. 



20 



3.4 



10 



20 



Survived. 



*These birds had needle-puncture of heart, or were bled from beak, to 

 obtain sugar samples after injection; this bleeding possibly partly responsible 

 for death. 



•"'Riddle, Amer. Jour. Physiol, 1916, xli, 387. 



