( 720) 
(5). 47.6 cc. Serum of the blood mixed with 0.024°/, CaCl, 
supplied 1) Ont tl or 00499 arr CASOE 
(6). 47.6 ce. Serum of De “blded mixed with 0.024°/, CaCl, sup- 
pleads ak dl Pisce oe 0.0492 or. CasQ,. 
(7). 47.6 ce. of the KR nd serum supplied 0.0369 gr. CaSQ,. 
(8). 47.6 ce. Serum of the blood mixed with 0.012°/, CaCl, 
supplied. . .. » «oh eee = a. 0.0487. cn CE 
9). 47.6 ce. Serum to which the same amount of CaCl, had been 
added as to the corresponding 80 cc. blood as sub (J) and 
sub (5) and (6) supply}. . =... . . 00596 er (ADE 
Comparison of the values in this table shows: 
1. that Ca has entered into the blood corpuscles (Cf. (B) with (1) 
and (4); 
2. that the blood corpuscles give up this Ca when brought back into 
normal serum. (Cf. (3) with (1) and (2). 
3. that the entire amount of Ca added to the blood is found back in 
blood corpuscles and serum. 
Moreover this table demonstrates that in the blood corpuscles of 
normal blood Ca is found (Cf. (3)). 
This last result clashes with the general opinion that in blood Ca 
is exclusively found in the serum. In the well known tables of 
ABDERHALDEN on the quantitative analyses of various kinds of blood, 
for instance, we find that everywhere Ca is being stated as absent 
from the blood corpuscles, and in FRANKEL: “Deseriptive Biochemie” 
p. 557 we read: “Das Calcium ist lediglich im Serum enthalten.” 
What may be the cause of this contradiction? We think that it 
is to be found in the method used for the quantitative determination 
of Ca. We know the metal has been determined as a sulphate or 
an oxalate, and it was tacitly taken for granted that these compounds 
are quite insoluble in the fluids in which they are found or very 
nearly so. This is by no means the case, especially not when the 
volume of the fluid is considerable. Close determinations of the 
solubility of CaSO, in acid alcohol have shown me that, besides a 
slight precipitate always visible after 24 hours, a great part of the 
CaSO, remains in solution. 
When we take this solubility into consideration it is found that 
the blood corpuseles contain a by no means negligible quantity of 
Ca, as is plainly shown by the figures in the preceding table. 
Still another method was applied to investigate the permeability to Ca, 
