74 THE BLOOD. 



the fulness and tension of the vessels and the quantity of fluid 

 that will exude from them to keep the tissues moist. Finally, 

 the water is the general solvent of all the other materials of 

 the liquor sanguinis. 



It is remarkable, that the proportion of water in the blood 

 may be sometimes increased even during its abstraction from 

 an artery or vein. Thus Dr. Zimmerman, in bleeding dogs, 

 found the last drawn portion of blood contain 12 or 13 parts 

 more of water in 1000 than the blood first drawn ; and Polli 

 noticed a corresponding diminution in the specific gravity of 

 the human blood during venesection, and suggested the only 

 probable explanation of the fact, namely, that, during bleed- 

 ing, the bloodvessels absorb very quickly a part of the serous 

 fluid with which all the tissues are moistened. 



The albumen may vary, consistently with health, from 60 

 to 70 parts in the 1000 of blood. The form in which it exists 

 in the blood is not yet certain. It may be that of simple 

 solution as pure albumen ; but it is, more probably, in combin- 

 ation with soda, as an albuminate of soda ; for, if serum be 

 much diluted with water, and then neutralized with acetic acid, 

 pure albumen is deposited. Another view entertained by En- 

 derlin is that the albumen is dissolved in the solution of the 

 neutral phosphate of sodium, to which he considers the alkaline 

 reaction of the blood to be due, and solutions of which can 

 dissolve large quantities of albumen and phosphate of lime. 



The proportion of fibrin in healthy blood may vary between 

 2 and 3 parts in 1000. In some diseases, such as typhus, and 

 others of low type, it may be as little as 1.034; in other dis- 

 eases, it is said, it may be increased to as much as 7.528 parts 

 in 1000. But, in estimating the quantity of fibrin, chemists 

 have not taken account of the white corpuscles of the blood. 

 These cannot, by any mode of analysis yet invented, be sepa- 

 rated from the fibrin of mammalian blood : their composition 

 is unknown, but their weight is always included in the estimate 

 of the fibrin. In health they may, perhaps, add too little to 

 its weight to merit consideration ; but in many diseases, espe- 

 cially in inflammatory and other blood diseases in which the 

 fibrin is said to be increased, these corpuscles become so numer- 

 ous that a large proportion of the supposed increase of the fibrin 

 must be due to their being weighed with it. On this account 

 all the statements respecting the increase of fibrin in certain 

 diseases need revision. 



The enumeration of the fatty matters of the blood makes it 

 probable that most of those which are found in the tissues or 

 secretions exist also ready-formed in the blood; for it contains 

 the cholesterin of the bile, the cerebrin and phosphorized fat 



