Hi. V. MeCollum and N. Simmonds 85 
Taken in connection with the results obtained in feeding the 
benzene extract of navy beans (Chart 1, Lot 953 A, Period 2), 
this experiment demonstrates the relative insolubility of the 
water-soluble B in hot benzene in animal tissues as well as in 
plant tissues. 
Lot 961 B. Period 1.—Ration: Purified food mixture plus 5 per cent of 
butter fat. 
Period 2.—Ration: Same as Period 1 but with 6 per cent of the residue 
after extraction of dry uncooked pig kidney with ether, then with acetone. 
Dry, uncooked pig kidney behaves toward ether and acetone 
in the same way as do the navy bean and wheat germ, in that the 
water-soluble B is not readily extracted even by prolonged 
treatment with these solvents. 
Lot 960 B. Period 1.—Ration: Purified food mixture plus 5 per cent of 
butter fat. 
Period 2.—Ration: Same as Period 1, but with the addition of the ace- 
tone extract of ether-extracted pig kidney equivalent to 6 gm. per 100 
gm. of ration. 
This experiment shows when considered along with Lot 961 B, 
that acetone does not readily extract the dietary essential, water- 
soluble B, from dried raw pig kidney. That a small amount was 
extracted is indicated by the fact that the animals in this group 
failed to develop the loss of muscular control except in one case, 
and this was at the end of the 7th week after the addition of 
acetone extract of kidney, and at the end of the 11th week of the 
experiment. Animals on the ration of Period 1 never live as 
long as this, which shows that the acetone extract furnished a 
little of the water-soluble B. Lot 961 B (Chart 11) was able to 
make appreciable growth, and although undersized was appar- 
ently normal. After the acetone extraction, the greater part 
of the water-soluble B was still in the residue. 
Preparation of the Extract and Residue Employed in the Ration 
of Lot 961 B and 960 B.—1,935 gm. of fresh pig kidney were 
ground up in a meat chopper and then dried at 95° for 24 hours. 
The weight of the dried kidney was 485 gm. which was equivalent 
to 25 per cent of the original weight of tissue. The dried residue 
was ground, then extracted with ether for 4 hours, and then 
ground up again and the extraction continued for an additional 
