30 Report OF DEPARTMENT OF BACTERIOLOGY OF THE 
In Thorp’s Dictionary of Applied Chemistry the solubility of 
chloroform is given as 1 volume in 200 volumes of water. Salkow- 
ski (2) gives it as 5cc. or 7.5 grams to the litre of water. Kirch- 
ner (1) found that a litre of blood-serum dissolved only 4cc. or 
6 grams. . 
METHODS OF EXPRESSING. SOLUBILITY, 
Since the specific gravity of milk is approximately 1 and that 
of chloroform is 1.48 there is a marked difference between per- 
centages expressed by weight and by volume. As a matter of 
convenience, mixtures of chloroform and milk are usually made 
upon a volumetric basis, and, in the literature of the subject, per- 
centages by volume are usually given. Accordingly, in the pres- 
ent publication all percentages given are to be taken as per- 
centages by volume unless the contrary is specifically stated. 
SOLUBILITY IN MILK. | 
In milk it is difficult to distinguish between solution and emul- 
sion when chloroform is added. When working with milk contain- 
ing 4 to 5 per ct. of fat, 25cc. or 2.5 per et. of chloroform 4s 
readily taken up by a litre; but when 5occ. is added, a portion 
settles to the bottom. Repeated shaking causes the chloroform 
to enter into intimate relation with the milk. In extended trials 
with both centrifugally-skimmed milk and with normal milk hav- 
ing a fat content of 4 to 5 per ct. chloroform was thus in- 
corporated with the milk in practically all percentages up to equal 
volumes of chloroform and milk. In a part of these tests the 
chloroform was added in portions of 2 to 5cc. in 200cc. of milk, 
while in other cases the additions were at the rate of 25 to 5o0cc. 
In these tests the chloroform did not separate from the milk even 
after standing some weeks. 
In the case of the larger percentages, it was very evident that 
something more than an ordinary solution was formed. The 
lower portion of the flasks was filled with a heavy, white, opaque 
layer, the thickness’ of which was proportionate to the amount of 
chloroform present. The tendency of chloroform to submerge 
fat is well known and this laver of fat tends to hide the other 
layer in normal milk unless the percentage of chloroferm is rela- 
tively high. The relation of the chloroform to the fat, as well as 
the nature of this white layer, will be discussed later. 
Taking advantage of the tendency of solutions to come to an 
equilibrium, duplicate bottles of milk were prepared containing ~ 

