THOMPSON YATES AND JOHNSTON LABORATORIES REPORT 
added, gave the necessary datum for calculating the amount of neutral fat which had 
been saponified by the alkali.' 
Experiment r. In this preliminary experiment only a small amount of chyle 
was collected (0-65 c.c), which contained 0*0198 grammes of ethereal extractive. But 
even this small amount was enough to demonstrate that the amount of free fatty acid 
present was relatively small, for on dissolving the ethereal residue in hot alcohol, and 
titrating as above described, it was found that only o* 1 c.c. of the decinormal 
alkali was sufficient to give a distinct pink with phenol-phthalein. Now, theoretically, 
the volume of decinormal alkali required, on the assumption that the ethereal extract 
consisted entirely of free fatty acid, would be 0*7 c.c. ; hence less than one-seventh of 
the extract was free fatty acid. 
Another indication of the presence of neutral fat and not fatty acid, which was 
also seen in the other experiments of this series, was the difficulty with which the 
ethereal residue dissolved in the alcohol. Neutral fat only dissolves in appreciable 
quantity when the temperature of the alcohol is near boiling point, while free fatty 
acid, such as oleic acid, dissolves appreciably even in cold alcohol. Hence, if a small 
quantity, such as a single drop, of olein be warmed with a considerable quantity of 
alcohol (50 c.c), it remains visible as a round globule until the alcohol is almost 
boiling. On the other hand, a much greater amount of fatty acid dissolves before the 
temperature of the alcohol is much raised. This qualitative sign is of considerable 
value in determining whether one is dealing with an extract consisting chiefly of 
neutral fat, or of fatty acid. In the series of experiments on digestion of soap with 
tissue extracts, it was found, in contra-distinction to those in the present series, that 
the ethereal extracts dissolved in the alcohol with great ease. 
Experiment 2. A dog, weighing approximately 12 kilogrammes, was fed with 
100 grammes of olive oil at 9 30 a.m. Anaesthetized at 3.30 p.m., exposed lacteals, and 
filled 17 drawn-out tubes with chyle, by cutting open lacteals. Weight of chyle = 
1*2990 gramme ; weight of total ethereal extract = 0*06 1 8 gramme ; weight of free fatty 
acid, calculated from direct titration = 0*0028 gramme ; weight of neutral fat, calculated 
from alkali required for saponification = 0*0564 gramme. 
Expressed as percentages of the total fatty matter, the neutral fat forms 95*3 
per cent., and the fatty acid 4*7 per cent. 
Experiment 3. A dog weighing 8*6 kilogrammes was fed with 50 grammes of 
olive oil at 9.30 a.m. At 4.30 p.m. (interval seven hours), the animal was anaesthetized 
with chloroform and ether, and 23 drawn-out tubes were filled with fatty chyle from 
the mesenteric lacteals, in which the amounts of fatty acid and neutral fat were es- 
timated as before, with the following results : — 
Weight of lymph = 0*9550 gramme. 
,, ethereal extract = 0*1052 ,, 
1. The abuve is Kottstorfer's method of estimating the amount of neutral fat (see Sutton's Volumetric Analysis, 
8th edition, p. 402) ; preliminary experiments with pure neutral olein gave practically theoretical results. 
