28 THOMPSON YATES AND JOHNSTON LABORATORIES REPORT 
reference to the protocolls given below, and the extent of such diminution of action 
is variable, but even after boiling the extracts for five minutes, a considerable effect 
has in many cases been obtained, and that in cases where bacterial action has been 
carefully excluded. This is particularly observable in the extracts of intestinal mucosa 
and lymphatic glands, where the difference between boiled and unboiled extracts is 
less than in the case of the pancreas. 
In fact, a considerable action has been observed in some cases after complete 
evaporation to dryness of the extract on a steam bath, on again adding water 
and soap and digesting at body temperature. 1 
It appears probable from this that the hydrolysis is not due entirely to an 
enzyme, but to some chemical substance with acid properties contained in the extracts 
which, at body temperature, slowly hydrolyses the soap and combines with the 
liberated alkali. 
If, instead of first boiling the extract and then adding the soap after it has 
cooled to 36° C. and digesting at that temperature, the soap be added to the unboiled 
extract and then the temperature be raised as rapidly as possible to ioo° C, a very 
rapid formation of free fatty acid, occurs, and the fatty acid floats at once in an oily 
layer on the surface of the extract even before the boiling point is reached. 
The extracts employed were in all cases alkaline to litmus, and the slight 
acidity to phenol-phthalein which they showed, like nearly all animal extracts, was 
found by titration to be much less than equivalent to the fatty acid liberated. 2 
b xcess of sodium carbonate stops the reaction, however, which does not 
occur when 0*5 per cent, of sodium carbonate is present in solution. 
Experiments on the Nature of the Fatty Constituents Present in the 
Mt-SENTERic Lymphatics During Fat Absorption 
In these experiments the lymph was obtained from the lacteals at a period of 
five to seven hours after feeding on neutral olive oil. 
The animals (dogs) were anaesthetized by a mixture of chloroform and ether, 
about five hours after feeding with the oil ; the abdomen was then opened and the 
intestine drawn out in small loops consecutively, so exposing the lacteals, which stand 
out clearly like silk threads, from being filled with the white, milk-like chyle. This is 
the appearance presented by the lacteals when first seen, but in a very short time, not 
exceeding five to ten minutes, they become discharged, and fat absorption appears to 
stop almost entirely. In making the collections of lymph, now to be described, it is 
hence necessary to proceed quickly, for the absorption is not restored very rapidly on 
replacing the loop of intestine and temporarily closing the abdominal wound, and if 
1. Sec Experiment I, Series iii, Addendum 2. 
In some of the experiments this acidity to phenol-phthalein was slightly over neutralized by addition of sodium carbonate 
solution. 
