212 THE STRUGGLE FOR LIFE. 
of the skin are organs of excretion and their action is 
absolutely necessary to life, as the poor fellow found whose 
whole skin was gilded to enable him to take part in an 
Italian pagent, since the result was to kill him. 
On the other hand, the glands of the alimentary canal 
secrete various substances, which so change the food, as to 
render it capable of absorption into the vessels of the body. 
I have neither time nor wish to describe the process of 
digestion, this wouid in itself require many evenings for its 
discussion. I need only say that the resultants of the 
interaction of the food with the secretions of the food-canal, 
differing in themselves widely, at different parts of its 
course, are absorbed, partly by delicate vessels called 
Lacteals, which finally pour their contents into a great vein 
at the root of the neck, and partly by the veins, these carry 
it into the liver where it is subjected to the influence of 
the cells of that organ before it also is allowed to mingle 
with the rest of the blood-stream. 
The amount of food which can be digested, absorbed, 
and made fit for the nutrition of the various parts of the 
body, strictly limits the supply of material available for 
nutrition. It necessarily follows from this, that, if one 
organ appropriates more than its fair share of the supply, 
other cells and tissues must go short and consequently 
suffer from the deficiency. 
In order that you may understand the remainder of my 
paper, I must give a short description of the blood, and of 
its circulation through the body. 
‘©The blood is the life,” said the Mosaic law. This, 
in one sense is quite true, for if the whole body be deprived 
of blood, or if it remain stagnant in the vessels for a short 
space of time, the animal dies at once. Cut off the supply 
from any part, as may be done experimentally by tying a 
ligature round a limb, the part beyond the constriction will 
quickly mortify. In passing, I may say, that this prohi- 
