TRANSACTIONS OF SECTION I. 959 
they are brought into relation, and would thus escape contributing any service to 
the economy. 
It is by enzyme action that the requisite adaptability is given for molecular 
combination, and Nature provides the suitable enzymes for giving to the food mole- 
cules the needed configuration for entering into the combination which is implied 
by the term ‘assimilation.’ The yeast cell constitutes a representative of living 
protoplasm; and, as with the protoplasm of the animal being, possesses no apti- 
tude for taking on cane-sugar molecules. By the agency, however, of invertase 
which the yeast cell produces the cane sugar is transformed into dextrose and 
lxvulose, and these are bodies possessing a molecular constitution suitable for the 
occurrence of combination with protoplasm. 
Thus, by enzyme action provision is made for the food molecules to be placed 
in a position to become incorporated into the living protoplasm that is located at 
the seat of absorption. Now, this living protoplasm consists of the lymphocytes 
_ which are observable in an actively growing state within the villi whilst digestion 
is going on. The active growth of these lymphocytes in connection with the diges- 
tion period is now recognised as an established occurrence, and their flow into the 
blood has given rise to the expression ‘digestion lymphocytosis’ by which the 
condition is now commonly known. 
Digestion, then, prepares not only for absorption, but likewise for assimilation. 
At the moment of absorption the products of digestion become taken hold of by 
the lymphocyte protoplasm and built up into an extension of it. Peptone and 
carbohydrate alike go into lymphocyte growth, and as the lymphocytes are formed 
they travel through the lacteal system—the channel constructed by Nature for the 
purpose—into the circulatory system, carrying with them the nitrogenous and car- 
bohydrate constituents of the food. Looked at in this way absorbed food reaches 
the blood through lymphocyte agency, and the accession of lymphocytes, occur- 
ring in association with digestion lymphocytosis, appears from the results of the 
blood-counting observations that have been conducted to be sufficient to adequately 
fit in with the circumstances. 
After increasing in number for a period of about five hours subsequent to the 
ingestion of food, the lymphocytes then diminish and fall to their minimum, pre- 
paratory to the nextintake of food. Taking place in the systematic manner it 
does, it may be reasonably assumed that the fall is due to a process of autolysis 
comparable to the autolysis occurring elsewhere. Autolysis is the result of a 
definite principle of action, and lysins of different kinds, standing in the position of 
enzymes, are produced to bring about the required effect. 
By lymphocyte autolysis the conditions are supplied for the production of the 
complex proteids of the blood. Fibrinogen, globulin, and albumin must obviously 
have a source in living protoplasmic matter. They cannot possibly be conceived 
to take origin otherwise than through the medium of protoplasmic growth. But 
little attention has been given to this point, and the proteids of the blood seem 
almost to be dealt with as though they were devoid of any definite source. 
A certain amount of experimental evidence has during the last few years 
been brought forward pointing to the lymphocytes constituting the source of the 
proteids of the blood ; and reasoning upon analogy drawn from collateral considera- 
tions there are strong grounds for entertaining the belief that they do so. The 
gland cells, like the lymphocytes, consist of living protoplasmic matter. They 
draw their element of growth from the nutrient constituents of the blood as the 
lymphocytes draw theirs from the constituents of the food. Having performed this 
office, and brought into play the special attributes belonging to them, they yield up 
by autolysis their formed material to the secretion which flows away. Growth in 
the first place, in accord with the specialised attributes existing, and autolysis in 
the next are cardinal phenomena associated with the manifestations of certain 
forms of cell life. 
The lymphocytes when they reach the blood fall in the comprehensive class of 
leucocytes. All possess the attributes of living protoplasm. They may be looked 
upon, I consider, as constituting the living element of the blood by which the 
standard composition of its plasma is maintained. ‘'T'o leucocytes the office of 
