THE DESQUAMATION AND DIGESTION OF SERPENTS. 55 



to me, in consideration of these phenonema, is whether a mistake 

 is not made in the reptile departments of menageries in keeping 

 the inmates at too high or too equable a temperature. Even in 

 the heart of the tropics, where there is very little distinction of 

 season, considerable variation must constantly be experienced 

 from local and accidental causes, and most likely this might be 

 imitated with advantage to reptiles in captivity. I have obtained 

 individuals at different times from broods born or hatched in our 

 own zoological gardens and in continental collections,-pythons 

 boas, and various colubrine snakes,-and in every case mine have 

 seemed to get on better than those which remained, though they 

 are exposed to many apparent disadvantages in a seafaring life- 

 irregular food-supply, exposure to air, and constant changes of 

 climate. I have come at length to the conclusion that they owe 

 their well-being to this change of climate and absence of fixed 

 artificial heat; and I have never known any of them suffer from 

 that irritable condition of the stomach, so often noticed in 

 menageries, which gives rise to constant rejection of the food, and 

 death from manition-though I have occasionally caused them to 

 vomit by inadvertently making their cages excessively hot in the 

 winter. The purest uric acid excrement which a serpent produces 

 is that passed immediately after its desquamation, because the 

 long period of inactivity which precedes it has enabled it to 

 convert all the nutritious material in its stomach. It has lately 

 been demonstrated that in comparatively cold countries, where 

 snakes have a well-marked and regular time of retirement during 

 a certain portion of the year, they lay up a stock of adipose tissue 

 in anticipation of their retreat, like other hybernating animals- 

 though naturally less in proportionate amount, owing to the 

 tardiness with which their vital functions are performed, and the 

 small quantity of fuel necessary for their consumption. 



There are probably many conditions under which the tem- 

 perature of a reptile varies independently of external influences, 

 which would be very interesting if properly worked out by patient 

 observers. We have seen more than once how, contrary to all pre- 

 conceived ideas and traditions on the subject, a pythoness actually 

 generates heat during incubation; and it is not unreasonable to 

 suppose that a similar development may take place concurrently 

 with active digestion, impending suppuration, or the progress of 



