12 OF THE BLOOD. 



the cruor is entire. The chief differences between the colouring 

 matter and fibrine are,, colour, the spontaneous coagulation ot 

 fibrine at all temperatures while the colouring matter may be 

 dried without losing its solubility in water and becomes insoluble 

 only at a certain temperature, and the peculiarity in the latter of 

 not diminishing in volume like fibrine during exsiccation. Albu- 

 men is intermediate between the two, and its only character of 

 distinction from fibrine is that it does not coagulate spontaneously, 

 but requires a high temperature. The brain and crystalline lens are 

 a sort of albumen 3 the epidermis, nails, hair, horn, cartilage, are 

 nearly composed of it ; of bone and muscle it is an essential part. 

 Fibrine exists in muscles only, besides the blood, and is indeed their 

 chief constituent, giving them form and rendering them fibrous. 

 Gelatine, or rather what becomes so by the agency of boiling water, 

 contains somewhat less carbon and more hydrogen than albumen, 

 and although not obtained from blood, is an important part of our 

 frame : the cutis, serous membranes, and tendons, are a species 

 of it, it forms the chief part of cellular membrane, and is an 

 essential constituent of bones, muscles, ligaments, hair, &c. The 

 composition of the substance of the viscera is not well known. 



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

 but Berzelius finds a larger proportion of nitrogen in that of the 

 bull, and by analogy I should think there must be a peculiarity in 

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

 various animals, yet our dishes disclose the greatest diversities. 

 Transfusion, or pouring the blood of one system into another, has 

 been practised for a century and a half, and satisfies us that the 

 blood, whether arterial or venous, of one individual, agrees well 

 enough with another of the same species ; but some late experi- 

 ments of Dr. Leacock/* and subsequently of Dr. Blundel, f render 

 it unlikely, contrary to the opinion of former experimentalists, 

 that the blood of one species suits the system of another. Dr. 

 Young found the large outer globules of the skate to be oval. 



* Medico-Chirurgical Journal. 1817. 



t Medico-Chirurgical Transactions. 1818. 



