IMPERFECT NUTRITION :—CONSUMPTION. 321 
igher animals at least, do the vessels directly pour the blood 
nto any tissue for the purpose of nourishing it. Unless there 
ave been an actual wound which has artificially opened the 
lood-vessels, no fluid can escape from them into the substance 
rayersed by the capillaries, except by transuding the walls of 
he latter ; and hence it would seem impossible that any of 
he floating cells contained in the blood can be deposited in 
he tissues and contribute to their development. The Liquor 
Janguinis seems, therefore, to furnish all that is wanting for 
his purpose ; and it readily permeates the walls of the capil- 
aries, the basement-membrane, and any other of the softer 
issues, so as to arrive at the parts where it is to be applied. 
As it is withdrawn from the blood, it is continually being 
e-formed from the food ; but if it be not supplied in sufficient 
juantity by the latter, the tissues are imperfectly nourished, 
nd the strength of the body and the vigour of the mind are 
onsequently alike impaired. 
386. This imperfect nutrition seems to be the essential 
ondition of one of the most destructive diseases to which the 
yuman frame is liable,—that commonly known as Consump- 
ion ; which is, however, but one out of several diseases that 
nay result from the same general defect of nutrition. If the 
iguor sanguinis be imperfectly elaborated, it is less fit to 
mdergo organization; and, consequently, instead of being 
onverted into living tissue, part of it is deposited, as an 
mperfectly organized mass, in the state known to the Medical 
nan as Tubercle. Such deposits take place more frequently 
n the lungs than in any other part ; and besides impeding 
he circulation and respiration, they produce irritation and 
nflammation, in the same manner as other substances im- 
yedded in the tissues would do ; and so far from having, like 
nany other diseases, a natural tendency to cure, this malady, 
f unchecked, almost certainly leads to a fatal termination. 
Microscopic examination of tubercular matter shows that it 
jonsists of half-formed cells, fibres, &c., together with a granu- 
ar substance which seems to be little else than coagulated 
umen. The only manner in which any curative means can 
brought to bear upon this terrible scourge, is by attention 
) the constitutional state from which it results. This is 
etimes hereditary ; and is sometimes induced by insuffi- 
nutrition, obstructed respiration, habitual exposure to 
¥ 
