39 
mass was then filtered and the curd washed ’v\dth distilled water. 
The whey thus obtained had a golden-yellow color and gave, vdth 
benzidin and also with alkahne phenolphthalin containing hydrogen 
peroxide, excellent tests for blood. On the other hand, the curd was 
practically white and showed but little blood by the benzidin and 
phenolphthahn tests. TTith benzidin the curd showed only a faint 
blue color; with alkaline phenolphthalin containing hydrogen per- 
oxide a little of the curd gave a deep pink color after standing for 
some time. 
A specimen of fresh cow’s milk, labeled (1), and another specimen 
of the same containing mouse’s blood, labeled (2), vrere kept at 
ordinary temperatme for six days. Both specimens had curdled 
and both were filtered. The serum of (1) was found to be clear 
and'^ almost colorless; the serum of (2) was clear and salmon pink 
in color. One drop of each filtrate was then added to 2 c. c. of the 
alkaline phenolphthalin-hydrogen peroxide reagent; (1) remained 
colorless, whereas (2) became pink immediately and ultimately deep 
purplish red. 
The residues left after filtering these two specimens of milk were 
washed with small amounts of distilled water and tested with the 
alkaline phenolphthalin-hydrogen peroxide reagent ; milk (1) remained 
colorless, and (2) gave a pink color after long standing. 
It is evident from these results that on acid coagulation the blood 
contained in cow’s milk passes almost entirely into the whey, and 
that the casein possesses but little if any adsorptive power for the 
blood pigments, the small amounts of blood present in the casein 
probably not being adsorbed but merely held in mechanical suspension 
by the casein. 
Fiu-ther tests for blood in milk have been carried out on hiunan 
milk containing known amoimts of human blood. Solutions of 
human blood in human milk were prepared as follows: 
(1) 0.0024 gram of blood, was dissolved in 1 c. c. of water; to this solution were 
added 5 c. c. of human milk B. 
(2) 0.0051 gram of blood was dissolved in 1 c. c. of water; to this solution were 
added 5 c. c. of human milk B. 
(3) 1 c. c. of solution (1) was made up to 10 c. c. with human milk B. 
(4) Consisted of human milk B alone. 
(5) Consisted of a second specimen of human milk, D, alone. 
These solutions were then tested towards the alkaline phenol- 
phthalin-hydrogen peroxide reagent, using 2 drops of the milk and 
2 c. c. of the reagent. After standing tluee minutes the solutions 
showed the following colors : 
(1) Red. 
(2) Deep purplish red. 
(3) Pink. 
(4) Trace of pink. 
(5) Trace of pink. 
