No. G30J 



FAMILY RELATIONSHIP 



51 



exert at first a very slight, but gradually cumulative, 

 effect; the homoiotoxins exert the maximum effect; and 

 then a decrease again takes place in the region of the 

 heterodifferentials. 



It might be suggested that the same auto-substances 

 play a part in the interaction between the normal tissues 

 of an individual. It is quite evident that the effect of 

 the autosubstances would be beneficial to the tissues and 

 contribute to their nourishment. Thus the body would 

 possess a system of very finely acting chemical auto- 

 regulators which keep the vascular supply at the point of 

 greatest intensity and prevent the fibroblasts from form- 

 ing dense fibrous tissue which again would interfere with 

 the nourishment of the tissues and which insure such an 

 interaction of tissues that the normal structure results. 

 Strange tissues do not exhibit the effect of such auto- 

 substances, even if such strange tissues should tempor- 

 arily multiply mitotically, and therefore they perish in 

 the end. 



On the other hand, autosubstances are indifferent, as 

 far as the lymphocytes are concerned, while syngenesio- 

 and homoio- and to some extent heterotoxins attract 

 them. The lymphocytes as well as invading fibroblasts, 

 are a destructive element and the effect of both is elimi- 

 nated through the action of autosubstances ; again a bene- 

 ficial adaptation. Hypothetically we might thus explain 

 in part at least the changes of tissues in old age. The 

 effect of the autosubstances would be strongest in young 

 individuals and decrease in the less actively metabolizing 

 older tissues ; and here we find, therefore, changes which 

 are characteristic of a decrease in the autosubstances, or 

 rather of specific metabolic substances which have the 

 auto" character and at the same time are characteristic 

 of the specific organ activity. Therefore in old age the 

 fibroblasts around the parenchyma from fibrous tissue 

 and the vascular supply decreases. In the embryo we 

 find least fibrous and most myxoid tissue and the best 

 vascular supply. 



