THE SERUM. 207 



which is thinly fluid, uncoagulable, and of a dirty brownish colour, 

 does not deposit fibrinous coagula, is easily infiltrated into the 

 tissues, but is generally found to occur in inconsiderable quantities 

 in the heart and the large vessels, while it is accumulated in abund- 

 ance in the capillaries. This condition is observed in true decom- 

 positions of the blood, as for instance, in pyaemia, puerperal fever, 

 scurvy, &c. 



We are still in the dark as to the direct origin of those polypous 

 coagula of fibrin which are deposited from uncoagulable blood con- 

 taining but little fibrin ; and all that we know in reference to the sub- 

 ject is, that the retarded circulation induced shortly before death by 

 mechanical obstruction as well as by debility, is favourable to the 

 deposition of these masses and hence their occurrence after a 

 protracted death-struggle. The formation of the purely local 

 fibrinous coagula observed in aneurisms, obliteration of the veins, 

 phlebitis, &c., may be explained in a similar manner. 



We now pass to the consideration of the actually dissolved 

 chemical constituents of the serum ; amongst which we must first 

 direct our attention to albumen. As we have already fully con- 

 sidered this substance in its various relations to other protein-bodies, 

 and to the other constituents of the blood (see vol. i., p. 342) it 

 only remains for us to notice one or two additional points. 



The question has often been raised, whether the albumen in dif- 

 ferent vessels, under different physiological relations, and in different 

 pathological conditions, is always identical. Physiological, no less 

 than logical grounds, warrant us in answering this question in the 

 negative, although chemistry affords but little aid in determining 

 the point. We have already seen (in vol i., p. 332) that many 

 modifications in the properties of albumen depend upon the 

 different quantity of alkali or salts which it contains, while the 

 organic group of atoms in the albumen has always remained the 

 same. Differences in the albumen, depending upon an augmenta- 

 tion or diminution of the quantity of alkali, that is to say, neutral, 

 basic, and acid albuminates of soda, occur even in the normal con- 

 dition, as for instance, in the blood of different vessels. The 

 solution of neutral albuminate of soda becomes turbid on the 

 addition of water. This combination occurs not only in morbid 

 blood (as Scherer was the first to show), but also in the blood of 

 different vessels, as also in the blood of the splenic vein ; and 

 here, independently of the other metamorphoses experienced by 

 the blood in the spleen, a portion of the basic albuminate of soda 

 is saturated by the free acid which we find in the parenchyma of 



