1862.] 



INCUBATION OF PYTHON SEBjE. 



367 



necessary experiments. The compartment of the Reptile-house in 

 which the Python is kept being warmed witli hot-water pipes, and 

 the temperature of snakes varying, as is well known, with that of the 

 surrounding medium, it seemed to me that the only mode of obtaining 

 reliable results was by comparison of the heat of the incubating female 

 Python with the heat of the non-incubating male, in the same com- 

 partment of the Reptile-house. It appeared to me that any decided 

 difference observable between these two animals, subject to exactly the 

 same external conditions, could be only attributable to the incubation. 

 Our first experiments with Negretti and Zambra's instruments were 

 made on February 12th, and gave a difference of 2°*8 of Fahrenheit's 

 scale in favour of the female, when the temperatures were taken at 

 the surface of the body. When the temperature was examined 

 between the folds of the bodies of the respective animals, the dif- 

 ference was found to be increased to 6°*8. The experiments were 

 repeated on the 23rd of February, the 2nd of March, the 9tli of 

 March, and the 16th of March, with varying results, but always 

 showing an increased temperature of greater or less amount in the 

 case of the incubating female, as the following Table will show : — 



These observations were made on the different occasions by Mr. 

 Bartlett, Mr. Negretti, Mr. Zambra, Mr, E, W. H. Holdsworth, 

 F.Z.S,, and myself. 



On the 4th of April the eggs were evidently decomposing, and 

 gave forth a very strong and nauseous odour. As the snake, which 



having manufactured expressly for these experiments the most sensitive and most 

 perfect thermometers ever constructed. In less than three seconds the quick- 

 silver will rise or fall from one end of the scale-tube to the other ; and although 

 a longer time than this has always been allowed by the reptiles in the experiments 

 made, it was most desirable to be provided with efficient means against any 

 emergencies. 



" The total length of the tube is 13 inches, and the bore, by actual measure- 

 ment, was found to be less than the ^o'^o th of an inch in diameter ; in the experi- 

 ments the motion of the mercury in it was watched with a powerful hand-lens or 

 magnifier. The range of the scale is from 30° to 105° ; the length of the bulb, or 

 reservoir for the mercury, ^ inch, its diameter ^ inch ; it is made extremely thin, 

 so as to insure the greatest sensitiveness by the quickest possible transmission of 

 temperature." 



* Not observed, the male being very restless. 



