1895 - 96 .] Mr D. F. Harris on Chemistry of Milk. 
85 
As to its precipitability by salts, I made a large number of obser- 
vations tending to show that decalcified caseinogen is, on the whole, 
more unstable than normal caseinogen in milk — a result perhaps 
due to the molecular disturbance consequent upon breaking up the 
union of the proteid with the calcic phosphate. 
VI. The Digestion op Milk “in vitro.” 
I had been often struck with the apparently unsatisfactory 
character of the artificial digestion of milk by means of *2 % 
HC1 and dry pepsine, in that no visible change appeared even 
after days on the water-bath. I thought it well to study the 
powers of coagulation of several artificial preparations, and their 
relative efficiency in digestion of milk as shown by the amount of 
caseoses or peptones formed. 
Three-quarters of a test-tubeful of fresh milk received a pinch of 
Bullock’s pepsina porci, an equal quantity of milk received a few 
m. -2 % HC1, a third tube had both HC1 and pepsine, a fourth 3ss. 
of Benger’s liquor pepticus + a little HC1, a fifth a little of a fresh 
glycerine-extract of the pig’s gastric mucosa, a sixth 3ss. of Benger’s 
liquor pancreaticus + a little 1 % sodium carbonate. 
At the end of 5' on the water-bath at 40° C., I reported — 
(1) In the tube with liquor pepticus there was a dense, tenacious, 
rope-like clot ; 
(2) In that with the liquor pancreaticus there was an exceed- 
ingly soft, friable clot, with as little cohesion as possible ; 
c 
(3) In that with the glycerine-extract there was a fairly firm 
clot, not so good as in (1). In none of the others was there any 
visible change. 
At the end of 30' no further visible change was to be observed. 
After five hours, the tubes with the pepticus and glycerine-extract 
showed some signs of a partial solution of the clot in each, but it 
was by no means marked. That with the pancreaticus contained 
a turbid fluid : all the clot had vanished ; the fluid was much more 
translucent than milk, and more so than the contents of any other 
tube. The superior translucency in this tube I attribute to the 
partial decomposition and saponification of the fat — a process 
which could not go on in any other tube. The second tube showed 
