466 Dr. Marcet on the Constitution of Blood [May 11, 



Fourth. That blood contains phosphoric anhydride and iron in a perfect 

 colloid state, or quite undiffusible when submitted to dialysis, the relative 

 proportions appearing to vary from 78*61 percent, of peroxide of iron 

 and 21 '39 of phosphoric anhydride, to 76*2 and 23*8 respectively, the 

 proportion of phosphoric anhydride having a tendency to be rather higher. 



Fifth. That blood contains more phosphoric anhydride and potash, 

 bulk for bulk, than serum. This fact has long been known ; but I have 

 shown that the excess of phosphoric anhydride and potash in the blood- 

 corpuscles is greater than can be accounted for by the estimation of the 

 proportions of colloid phosphoric anhydride and potash in blood and 

 serum ; consequently there exists in blood-corpuscles a power checking the 

 diffusion of the diffusible substances they contain, and apparently con- 

 nected with a force peculiar to the corpuscles, as this force ceases to act as 

 soon as the corpuscular form disappears from admixture with water. This 

 property inherent to blood-corpuscles may cause an accumulation of 

 potash in blood equal to no less than rather more than four times the 

 amount of this substance present in an equal bulk of the serum of the same 

 blood. 



Sixth. That a mixture of colloid phosphoric anhydride and potash can 

 be prepared artificially by the dialysis of a solution of chloride of potassium 

 and phosphate of sodium, and that the colloid mass thus obtained appears 

 to retain the characters of the neutral tribasic phosphate from which it orU 

 ginates ; it exhibits an alkaline reaction, yields a yellow precipitate with 

 nitrate of silver, and after complete precipitation the reaction is acid. 



Seventh. That by dialyzing certain proportions of phosphate of sodium 

 and chloride of potassium during a certain time, proportions of phosphoric 

 anhydride, potash, chlorine, and soda are obtained in the colloid fluid very 

 .similar to the proportions these same substances bear to each other in 

 serum after twenty-four hours dialysis. 



Eighth. That muscular tissue is formed of three different classes of 

 substances,— the first including those substances which constitute the 

 tissue proper, or the portion of flesh insoluble in the preparation of the 

 aqueous extract, and consisting of an albuminous principle and phosphoric 

 anhydride with varying proportions of potash and magnesia ; the second 

 class including the same substances as are found in the tissue proper, and 

 in the same proportions relatively to the albumen present in that class, but 

 existing in solution and in the colloid state ; the third class including the 

 same substances as are found in the two others, and moreover a small 

 , quantity of chlorine and soda, which, although relatively minute, is never 

 absent. The constituents of this class are crystalloid, and consequently 

 diffusible, the phosphoric anhydride and potash being present precisely in 

 the proportion required to form a neutral tribasic phosphate, or a pyro- 

 phosphate, as the formula 2KO P0 5 can equally be 2KO HO P0 5 . The 

 formation of this substance (2 KO PO.) is extremely interesting, and shows 

 beyond a doubt that, in addition to the material blood yields to muscu- 



