120 MANUAL OF HISTOLOGY. 



matters containing phosphorus" found in the blood might possibly 

 belong to the cell, was subsequently shown by Lehmann to be quite cor- 

 rect. The cells of venous blood, moreover, appear to be richer in these 

 cerebral substances than those of arterial blood. 



Of the products of decomposition of the blood-corpuscle but little is 

 as yet known, except that hsematoidin ( 35) may be regarded as a trans- 

 formation product of blood-cells breaking down in the living body; as 

 also bilirubin ( 37), and in all probability cholestearin. 



As far as these matters generated by the trans mutative power in the 

 cell do not rapidly leave the latter, or undergo further metamorphosis 

 immediately, they appear in the uninteresting form of the so-called extrac- 

 tive matters (p. 54, remarks). 



Finally, the nature of the mineral constituents, proper to the cell in 

 contradistinction to those of the plasma, is of great interest, an aspect of 

 blood analysis first brought under notice by C. Schmidt. Among the salts 

 of the blood-cell there appear some which are soluble in water, but in 

 smaller quantity than if the cell were simply saturated with plasma. 

 Further, the cell appears to be poorer in chlorine, but richer in phosphoric 

 acid than the plasma; it likewise shows a much larger proportion of 

 potash, and on the other hand a considerably smaller one of soda than 

 the latter fluid. Thus, we find in it principally the phosphates of the 

 alkalies, together with chloride of potassium, whilst chloride of sodium 

 preponderates in the liquor sanguinis. The latter is, moreover, richer in 

 phosphatic earths than the cell. 



Now, since iron is not met with in the intercellular fluid (C. Schmidt), 

 all of this metal which exists in the blood must be contained in the cells. 

 Copper, also, and manganese (whose presence in. the blood, however, must 

 be still regarded as doubtful), ought also, according to analogy, to belong 

 to the contents of these elements. 



Finally, the red corpuscles possess of gases almost all the oxygen of 

 the whole fluid, which gas is retained in loose chemical combination 

 with the haemoglobin, a fact which may be looked upon as the greatest 

 in physiological significance of any yet adduced in connection with the 

 little structure in question. Besides this, the corpuscles contain a con- 

 siderable amount of carbonic acid (A. Schmidt). 



What the nuclei of the blood-corpuscles of the lower vertebrate animals 

 consist of is not yet known with certainty; it is generally supposed to be 

 of some albuminous substance like fibrin, although a recent observer, 

 Brunton, believes them to be composed of mucin. 



75. 



The number of substances held in solution by the intercellular fluid of 

 the blood is still more considerable than those contained in the cell. 



First of all, we meet in the plasma with several matters belonging to 

 the albuminous group. 



In the first place, the two constituents of fibrin, namely, fibrinogen 

 and tibrinoplastin, the latter finding its way into this fluid from the 

 blood-cells ( 11). Coagulated fibrin formed from these appears in the 

 proportion of about 4 in 1000 parts of liquor sanguinis, but is liable to 

 vary considerably as to quantity, even in the healthy subject. 



Albumen (serum albumen), which, as previous analyses have shown, is 

 contained in far larger proportion in liquor sanguinis than fibrin, is very 

 probably held in solution by salts. 



