84 
DR. REES ON THE CHEMICAL ANALYSIS OF THE CONTENTS OF 
able quantity from the chyle of the Ass, and found it to exhibit peculiar characters, 
which I have described in the Medical Gazette for January 1, 1841, to which I may 
refer also for a comparative analysis of the chyle and lymph of this vegetable feeder. 
It has frequently been stated by observers, that chyle, when set aside to coagulate, 
assumes a pink colour if exposed to the air ; this is stated to be the case by Muller 
in the chyle from the thoracic duct of the Horse. My own observations do not agree 
with this statement ; for fluid taken from the thoracic duct of the Dog, Ass, and Cat, as 
also that lately obtained from the human subject, showed no such change of colour 
when under the conditions mentioned by Muller. There were, indeed, a few blood-cor- 
puscles to be seen by microscopic examination ; but these were so few in number and 
so divided as not to manifest their colour, and were, I have no doubt, taken up by the 
divided mouths of some of the absorbents which emptied themselves into the thoracic 
duct during the period occupied by us in obtaining its contents. Mr. Samuel Lane 
was, I believe, the first observer who traced the existence of the blood-corpuscle in 
the chyle to its true cause, and showed that chyle might be procured free from such 
contamination, if the contents of the thoracic duct were speedily obtained. I have 
had occasion in this analysis to verify my former views concerning the cause of the 
white colour of the chyle, which 1 feel confident is chiefly attributable to its contain- 
ing the opake white salivary matter as a constituent. This substance is always, 
however, mixed with a certain proportion of fatty matter. It may be obtained from 
chyle by agitation with ether ; when we find it to subside through the ether, and to 
float on the surface of the chyle which has now become cleared. 
The microscopic examination of human chyle has been much neglected. From 
the appearances observed in the specimen lately obtained, I am enabled to state 
that its corpuscles are of the same description as those in the chyle of purely animal 
and vegetable feeders. They consist of two classes, viz. — 1. Larger spheroidal bodies, 
varying in size, but for the most part larger than the blood-corpuscles, semitranspa- 
rent, and granular on the surface. The largest of these corpuscles are nearly twiee 
the diameter of those of the blood. 2. Minute granules varying in size from about 
Ygth the diameter of the blood-corpuscle to a size which scarcely admits of their 
being seen, except by the aid of a perfect light and a microscope capable of magni- 
fying to about 750 diameters, when they appear to form a kind of back- ground on 
which are seen the larger corpuscles first noticed. These granules have been de- 
scribed by Messrs. Lane and Gulliver as existing in the chyle of animals. Mr. 
Lane has likewise described a molecular motion in them, which I have had occa- 
sion to verify. Besides these corpuscles and granules we also detect fatty globules 
in the chyle, varying greatly in size. If we compare the analysis I have given of the 
contents of the thoracic duct with the analysis of the blood, we cannot fail to be 
struck with the very great excess of fatty matter existing in the former. We have 
a large quantity of an hydrocarbonous ingredient constantly entering the blood, 
and becoming consumed with great rapidity, as proved by the small percentage 
