366 DR. p. L. SCliATEU ON THE [DeC. 9, 



This pair of Pythons were several times observed in co2mld by the 

 keeper, in the month of June 1861. Towards the middle of December, 

 1861, the female was remarked to be much increased in size, the 

 enlargement extending about 8 feet along the body. The keeper, 

 knowing that she had not fed for many weeks, imagined this altera- 

 tion of size to be the result of disease ; and it was only a few days 

 before the 13th of January that the true cause of h^r abnormal 

 appearance was suspected. On the morning of the 13th of January 

 the keeper found that in the course of the previous night this animal 

 had deposited a large mass of eggs, and had taken up a position 

 coiled completely round them, so as nearly to exclude them from 

 view. The eggs, as we afterwards ascertained, were about 100 in 

 number ; they were nearly round in shape, but soft, and soon became 

 much compressed, measuring each about 3 inches in diameter. They 

 seemed to have been deposited in a circle, probably from the creature 

 crawling round, and excluding them one after the other. They 

 were not strung together by any membrane, but apparently com- 

 pletely separate when excluded, though afterwards fastened into one 

 large conical mass, adhering by the viscid outer membrane, and 

 pressed together by the weight of the superincumbent mother. 



The Python retained her position coiled round and over the eggs 

 more or less constantly until the eggs were eventually removed on 

 the 4th of April. During this time she quitted them upon very few 

 occasions, and then only temporarily, having passed altogether nearly 

 thirty- three weeks without taking food. 



On the 4th of March the Python showed symptoms of being 

 about to cast her skin, and was then off her eggs from 9 p.m. until 

 7 a.m. on the following morning. During this interval the skin came 

 off in shreds (always an unhealthy symptom in snakes), the process 

 lasting about 1 hours instead of 3 or 4, as is usually the case with 

 these large serpents. 



Knowing the interesting nature of M. Valenciennes' s experiments 

 on the temperature of the Python which incubated in the Jardin des 

 Plantes at Paris in 1841*, I was anxious to ascertain whether any 

 similar increase of temperature was observable in the present case. 

 The instruments first employed for this purpose were not sufficiently 

 delicate to produce any very reliable results. I therefore applied to 

 Messrs. Negretti and Zambra, the well-known optical instrument- 

 makers, who provided thermometers expressly adapted for the 

 purposef and kindly attended themselves to assist in making the 



* For an account of these, see * Comptes Rendus/ 1841, xiii. p. 126. 



t These thermometers are spoken of as follows in the ' London Review ' for 

 March 15th : — 



" In testing the heat of the incubating Python and her eggs, it will be readily 

 imagined that the most sensitive thermometers would be required to obtain reli- 

 able and satisfactory results, not only on account of the possible danger, through 

 disturbing and irritating the snake, of her striking and giving the operator a 

 lacerated wound with her pointed teeth, but from the desirability of obtaining as 

 instantaneous results as possible to avoid the interference of cold drafts of air, 

 alterations of the creature's position, and other circumstances which must produce 

 interferent effect. To Messrs. Negretti and Zambra the highest praise is due for 



