&64 



MR. W, A. FORBES ON THE INCUBATION [NoV. 29, 



case more than half the eggs hatched out, it may be that the faihive 

 of our animal to do the same was due to the lack of heat. There is 

 also in our case none of tliat steady fall in temperature, from the 

 commencement to the close of incubation, observed by Valenciennes. 

 In his case, at the commencement of incubation the female had a 

 temperature of 41°-5 C. (106°v F.) between the folds (the highest 

 observed at all), falling at the end to 28^ C. (82°-4 F.). In our 

 case, the maximum temperature was very nearly obtained on three 

 different occasions. 



The second set of observations, those made here in 1862, are 

 hardly complete enough to allow of much comparison ; but through- 

 out that series (he differences between the sexes are greater, though 

 the absolute temperatures are considerably lower ' than the average 

 ones I obtained. 



Renewed observations will be required to satisfactorily settle the 

 amount of the increase of temperature — a fact of which there can 

 now, I think, be no doubt — which is produced in these reptiles by 

 the process of incubation. The average difference of 3° V. which 

 I have obtained is, it may be observed, very nearly identical with 

 that which occurs in the case of the temperature of fever-patients 

 as compared with the normal. And as the increase of heat in an 

 incubating bird is essentially of the same nature as that produced 

 by an inflammation of a tissue, and such is also presumably the case 

 in an incubating reptile, the nearness of the results thus arrived at is, 

 in itself, an argument in favour of the correctness of my observations. 



Table I. 



Record of Observations on the Temperature of the incubating {Female) 

 and non-incubadncf (Male) Pythons. 



1 Except in the case of one i-eading of 96° F., taken on the female, which was 

 on that clay 20° F. warmer than the male. This observation, however, is, I 

 think, open to doubt. 



