~ Coal 
256 TRANSACTIONS OF THE CANADIAN INSTITUTE. [Vo. VIII. 
oil without previously depriving it of food and killed it about 
twenty hours later. A piece of the duodenum was put into five per cent. 
chloral hydrate over night, then placed in the scarlet red solution 
for about twelve hours, removed therefrom to water for a few seconds, 
then teased in glycerine and mounted, and the edge of the slip being subse- 
quently smeared with paraffin. The result was quite remarkable, (Fig. 18). 
In some instances the droplets were irregularly scattered throughout the 
border, in others they were arranged in beadlets running parallel with the 
striz, in others again a string of beadlets is seen running transversely 
to the plane of the bodies, and at the very tips of the striz, as though 
the beadlets were just entering the cell, while in still others the same 
elongated form of the fat droplets, as described in the guinea pig, is evi- 
dent. The same technique was carried out ‘with the dog, kitten, frog 
and Necturus and in each instance I was able to demonstrate fat particles. 
in the striated border (Figs. 13, 18 and 109). 
The question naturally arises: Why cannot these fat particles be 
demonstrated with osmic acid? That it fails in paraffin sections I believe can 
be accounted for by the slight solvent action of the alcohols used. While 
it is. tme that alcohol is not an active solvent for fat since you can put 
fat-fed specimens which have been fixed in formalin and cut with the 
carbon dioxide freezing method into seventy per cent. alcohol for an hour, 
then into ninety-five per cent. for fifteen minutes, all without any 
appreciable difference in the fat reaction when afterwards stained with 
scarlet red, yet when long continued it might readily affect that which is. 
most accessible. It must be borne in mind, also, that osmic acid is not as. 
delicate, or as sensitive a stain, for fat as scarlet red. 
During the last few days of my investigation I directed my attention 
to the demonstration of fat droplets in the border by means of osmic acid. 
A rabbit was fed 20 c.c. olive oil, without being previously starved, 
and killed three and a half hours later. Pieces of the duodenum were put 
into five per cent. chloral hydrate over night and then into one per cent.. 
aqueous osmic acid solution and small portions teased out from time to 
time in glycerine. The osmic acid penetrates very slowly under such cir- 
cumstances so that not until about the fourth day do you get any marked 
reaction. Fig. 21 shows the appearance of the cells after four days in the 
osmic solution. Here too one can see fat beadlets in the striated border, 
and when compared with Fig. 19 the similarity is striking. 
From the above considerations it is evident that fat can be and is 
absorbed in some particulate form. By means of scarlet red it is not 
