162 ON INJECTING THE LYMPHATIC SYSTEM OF REPTILES, 



are injected. When it is required to make a warm injection, the animal 

 is placed in tepid water, and the injection is melted in a sand-bath. I 

 do not dilate further on this subject, as I hasten to inform you that 

 since my last letter, I have made some researches on other reptiles, and 

 have found that land-tortoises, lizards, and snakes, are organized so far 

 as regards the lymphatics, similarly to frogs and salamanders. In the 

 snake I have seen a vein enclosed in a lymphatic vessel, but on this 

 point I am not quite certain, not having at my disposal but two or three 

 of those reptiles which were extremely small. 



During the period of these researches it occurred to me to destroy 

 the tortoises under observation by prussic acid. I was surprised to find 

 them almost resist the poisonous action of this acid ; I say almost, be- 

 cause the doses which caused the immediate death of a cock, cat, or 

 a dog, do not sensibly affect them ; so that to kill a tortoise of twelve 

 centimetres in length, I have been obliged to inject into the stomach 

 by the aid of a syringe, a dose of this poison which would have been 

 more than sufficient to kill a horse, and after all it did not die until 

 fifteen hours. But to return to the lymphatic vessels : 



When I announced to you the result of my observations on frogs 

 and salamanders I was entirely ignorant that M. Weber, Professor of 

 Anatomy at Leipsic, had inserted in Miiller's Archives, 1835, an article 

 on the hearts and lymphatic vessels of Python tigris. This observer 

 has remarked that the lymphatics of this serpent are very large, and 

 that the greater part of the arteries and even of the veins are enclosed 

 in those vessels, but always separated from one another. He has ob- 

 served that the aorta and its ramifications, even to the smallest, are en- 

 veloped in such a manner as to be bathed by the lymph : you see then 

 that it is to M. Weber that the merit of the discovery of this fact is due, 

 which entirely escaped the researches of Panizza. 



One reflection occurs to me, and I cannot refrain from communicating 

 it to you : M. E. Weber has made the dissection of but one reptile, the 

 Python tigris, (which is seven feet long,) and he has enriched science 

 with a very singular fact. Five years after I dissected a very small rep- 

 tile in comparison, and I discovered the same fact. Panizza has dis- 

 sected several land tortoises, but they were not sufficiently large for the 

 experiments he had in view ; he then procured several turtles. He has 

 besides dissected many snakes, lizards, frogs, and salamanders, and in 

 spite of all these opportunities, the fact of which I have spoken, al- 

 together escaped his investigation. You will not be surprised at this 

 when you recollect, that in all his experiments he employed the injecting 

 tube of Walter and mercury. If he had made use of a syringe, and a 



