THE THORACIC DUCT IN THE HUMAN SUBJECT. 
85 
of fatty matter contained in the mass of blood. Whether this hydrocarbonous 
matter is exhaled by the lungs and skin in the form of water and carbonic acid, or 
whether, on the contrary, an absorption of nitrogen and oxygen occurs in the process 
of respiration, so as to convert the fat of the chyle into albuminous matters for the 
purposes of secretion and nutrition, is not yet determined ; many circumstances, how- 
ever, seem to favour the latter view ; thus, the chyle of an animal fed on beans and 
oats, substances very different in quality from fatty matters, is found to contain a very 
large proportion of fat, destined, no doubt, for some useful purpose of the animal 
economy, and which would scarcely be produced from aliment in order to be sub- 
jected to a direct process of excretion. The proportion of “ extractive matter soluble 
in water and alcohol” or osmazome, will be found greatly to exceed the amount of 
that principle contained in the blood ; agreeing well with what we know concerning 
the universal distribution of this substance as a constituent of the soft parts of the 
human frame. 
