158 LYMPHATIC SYSTEM. 



from which such conclusions were made, with respect to 

 these fluids, it will appear in the sequel, that although they be 

 so transparent in living animals, and so watery in dropsies, yet 

 in animals in health they differ so much from water, that they 

 not only coagulate when exposed to heat, but also when merely 

 exposed to the air; in which circumstance they agree most 

 with that part of the blood called the coagulable lymph, as is 

 evident from the following experiments. 1 



EXPERIMENT I. 



If, soon after killing an animal in health, the abdomen, tho- 

 rax, or pericardium be opened, and if a little of the fluid that 

 moistens these cavities be collected, which (even in cases where 

 the quantity is very small) may be done by gently scraping the 

 surface of these cavities with a wet teaspoon, and if the fluid 

 thus collected be suffered to rest, exposed to the air, it will 

 jelly as the coagulable lymph of the blood does. This is an ex- 

 periment which I have made on a considerable number of ani- 

 mals, viz. on bullocks, dogs, geese, and rabbits, and the result 

 of all the experiments was the same (LXVIII). 



EXPERIMENT II. 



If, immediately after killing an animal in health, a lymphatic 

 vessel be tied up properly, and then cut out of the body and 

 opened, so as to let out the lymph into a cup and expose it to 

 the air, it will jelly as the coagulable lymph of the blood does 

 in the same circumstances ; this experiment I have likewise 

 made several times on dogs, asses, and geese. 



1 From amongst those who concluded these fluids a mere water should be excepted 

 M. de Haller. (See his El. Phys.) And Professor Monro says they coagulate by cold 

 and rest. (Ob. An. and Ph. p. 68.) 



(LXVIII.) The fluid from the pericardium of horses, shot on account 

 of lameness, does not always coagulate spontaneously, as I have ascer- 

 tained ; yet it did in two trials, as mentioned in Note xvm, p. 31, when 

 mixed with serum from the same animal's blood. I carefully looked 

 into the pericardium of each of the four suffocated human subjects 

 noticed in Note xxxin, p. 69, and found no coagulated lymph what- 

 ever, nothing but a little straw-coloured and transparent fluid, not more 

 than from a quarter to half a drachm in each pericardium. Some 

 colourless fluid which coagulated spontaneously from the belly of a 

 tortoise, is mentioned in Note xxvn, p. 53. 



