686 LECTURE XXX. 



finally begin to participate in removing the foreign substance by an in- 

 creased elimination of secretions. The animal organism under normal 

 circumstances constitutes a well-protected entity. Nothing foreign can 

 penetrate into the cell-metabolism, consequently the general metabolism 

 proceeds along its usual course. It becomes an entirely different matter 

 when material is presented to the cells which can turn the whole organiza- 

 tion toward an entirely different direction. There are constantly cells in 

 our body which are engaged in process of destruction, and others, which 

 here and there renew an important foundation stone, or even entirely 

 reconstruct it. The body-cells have become adapted to a definite nutri- 

 tion through many generations, and confine themselves to material which 

 is useful to the whole organism. During infection, the blood will trans- 

 port substances which are evidently closely related to normal nutrient 

 materials. 



This assumption seems all the more probable when we suggest that we 

 can easily imagine how in the preparation of the building-stones of a cell, 

 not only the -cell in question is active, together with its neighboring cells, 

 but there must be an intimate exchange of the products of metabolism on 

 the part of the separate cells. Now the toxines are merely products result- 

 ing from the metabolism of cells. If these products become a part of a 

 body-cell, then immediately the entire function of such a cell is changed. 

 It will, as before, receive and give up substances to the fluids of the body, 

 but the substances now given up will be of an entirely different character, 

 for the function of a cell is a result of its own composition. We can easily 

 understand how, if a single constituent of a cell is altered, all the chemical 

 processes may take place in a different direction. If the cell is not badly 

 injured it will continue to function. Naturally the subsequent absorp- 

 tion of material will take place in accordance with the altered conditions, 

 and thus the peculiar nature of such cells will gradually make itself felt. 

 Among the thousands of body-cells, it is not necessary that many of them 

 should be attacked, perhaps only those which were in the process of under- 

 going a transformation. We know that in chemical processes the slightest 

 deviation in the conditions may cause the reaction to take place differently. 

 How much more must a continuous change in the nature of the metabolic 

 products affect the normal course of processes which take part in the cell 

 construction! We wish to affiliate this conception of Ehrlich concerning 

 the formation of antitoxines more closely with processes of metabolism, 

 and especially in order to avoid leaving the impression that the formation 

 of these side-chains is an abnormal function of the cells. The different 

 toxines are naturally differently constituted, and it does not seem at all 

 strange that the cells of the various tissues should take up these toxines 

 in different degree, and that, for instance, the cells of the nerve tissues 

 should be peculiarly adapted to unite with tetanus poison. This toxine 



