THE BLOOD. 159 



four adult water-newts (lacerta palustris), which had been just caught, and 

 weighed each an ounce and a half, 9 iijss. of blood. The proportion to the 

 weight of the body was as 2^ to 36, while in healthy adult men it is as 1 to 5." 

 (Compar. Anatomy, ch. xii. ed. i. p. 245. Translated by Mr. Lawrence.) 



The blood of different brutes coagulates in different times. Mr. Thackrah 

 imagines the rapidity to be inversely as the strength and size. Thus, while in 

 health, human blood coagulates in from 3 or 4 to 7 minutes, that of the 



Horse, in from 2 to 15 



Ox, 2 to 10 



Dog, $ to 3 



Sheep, hog, rabbit i to 1 



Lamb, 5 to 1 



Fowls, ^ to li 



Mice, in a moment. 



Fish, according to Hunter (1. c. p. 211.), also in a moment. 



The blood of brutes has the same general character as our own, and Rouelle 

 obtained the same ingredients, though in different proportions, from the blood of 

 a great variety of them. Berzelius finds a larger proportion of nitrogen in 

 that of the ox, and analogy would lead us to suppose there is a peculiarity in 

 the blood of every species. Muscles look pretty much alike in various animals, 

 yet when cooked they disclose the greatest diversities. Transfusion, or pouring 

 the blood of one system into another, satisfies us, that the blood, whether arterial 

 or venous, of one individual, agrees well enough with another of the same 

 species ; but some late experiments of Dr. Leacock (Medico- Chirurgical Jour- 

 nal, 1817, p. 276.), and subsequently of Dr. James Blundel (Medico- Chirurgical 

 Transactions, 1818), render it unlikely, contrary to the opinion of former ex- 

 perimentalists, that the blood of one sjwcies suits the system of another. Dr. 

 Young found the large outer globules of the skate to be somewhat almond- 

 shaped, and Hewson found them of different shapes in different animals, and 

 Rudolphi observed them to be more or less oval in the common fowl and many 

 amphibia. (Grundnss der Physiologie, 159.) MM. Prevost and Dumas have 

 noticed, in their microscopic experiments, a great difference in the blood of 

 different animals as to the globules, and in this way explain the impossibility of 

 transfusing the blood of some animals to others without danger to life. They 

 assert that the quantity of the particles is proportionate to the temperature of the 

 animal, and that, consequently, most exist in the blood of birds : that the size 

 and shape also vary, although the size of the central portion is the same in 

 animals in which they are spherical, and is about t^fa of an inch in diameter : 

 and that the shape of the external part is circular in the mammalia, and elliptical 

 in birds (M. Raspail says, in oviparous quadrupeds also) and cold-blooded 

 animals, thus confirming and generalising the observations of others, for Hew- 

 son observed the difference of their size in different animals, and that this bore 

 no relation to the difference in the size of the animal (1. c. part iii. p. 10. sqq.) : 

 and they find the shape of the central portion correspondent with that of the 

 external, spherical when the latter is circular, oval when elliptical. They 

 assert that, if the blood of two animals of different species, the blood of one 

 of which was transfused into the other, differed in the size only of the globules, 



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