IMPERFECT NUTRITION :—CONSUMPTION. 
321 
higher animals at least, do the vessels directly pour the blood 
into any tissue for the purpose of nourishing it. Unless there 
have been an actual wound which has artificially opened the 
blood-vessels, no fluid can escape from them into the substance 
traversed by the capillaries, except by transuding the walls of 
the latter; and hence it would seem impossible that any of 
the floating cells contained in the blood can be deposited in 
the tissues and contribute to their development. The Liquor 
Sanguinis seems, therefore, to furnish all that is wanting for 
this purpose; and it readily permeates the walls of the capil¬ 
laries, the basement-membrane, and any other of the softer 
tissues, so as to arrive at the parts where it is to be applied. 
As it is withdrawn from the blood, it is continually being 
re-formed from the food; but if it be not supplied in sufficient 
quantity by the latter, the tissues are imperfectly nourished, 
and the strength of the body and the vigour of the mind are 
consequently alike impaired. 
386. This imperfect nutrition seems to be the essential 
condition of one of the most destructive diseases to which the 
human frame is liable,—that commonly known as Consump¬ 
tion ; which is, however, but one out of several diseases that 
may result from the same general defect of nutrition. If the 
liquor sanguinis be imperfectly elaborated, it is less fit to 
undergo organization; and, consequently, instead of being 
converted into living tissue, part of it is deposited, as an 
imperfectly organized mass, in the state known to the Medical 
man as Tubercle. Such deposits take place more frequently 
in the lungs than in any other part; and besides impeding 
the circulation and respiration, they produce irritation and 
inflammation, in the same manner as other substances im¬ 
bedded in the tissues would do ; and so far from having, like 
many other diseases, a natural tendency to cure, this malady, 
if unchecked, almost certainly leads to a fatal termination. 
Microscopic examination of tubercular matter shows that it 
consists of half-formed cells, fibres, &c., together with a granu¬ 
lar substance which seems to be little else than coagulated 
albumen. The only manner in which any curative means can 
be brought to bear upon this terrible scourge, is by attention 
to the constitutional state from which it results. This is 
sometimes hereditary; and is sometimes induced by insuffi¬ 
cient nutrition, obstructed respiration, habitual exposure to 
