542 OLD AGE. 



which attributes a preponderating part to the attack on the valuable 

 elements made by the macrophages is not a mere plausible speculation, 

 but rests on numerous and exact facts. It would be interesting to 

 penetrate more deeply into the causes of this drama which is being 

 played Avithin our own organism and which occasions such serious 

 evils. Unhappily science is not sufficiently informed to satisfy an 

 investigating spirit otherwise than by the aid of hypotheses. 



III. 



It has often been said that old age is a kind of disease. In fact the 

 great resemblance between these states is incontestable. Among the 

 maladies to Avhich an organism is subject there is a considerable group 

 that manifest themselves in the form of atrophies. Sometimes it is 

 an atrophy of muscles which occasions a consideral)le weakness in 

 the voluntary movements and in which Ave find proliferation of the 

 nuclei, as in the muscles of old people. Atrophic maladies of the 

 kidneys and of the liver are numerous, and in these we find a dis- 

 appearance of the glandular tissue and its replacement by connective 

 tissues the same as we find in old ago. Atrophy t)f the osseous sub- 

 stance produced by giant cells often occurs in the course of certain 

 maladies. In all these examples the more j^rofoundly we study the 

 lesions the more we become convinced of their similarity to those 

 which take place during old age. 



Although the cause of many of the atrophic maladies is still un- 

 known, thei-e are nevertheless some Avhose origin is sufficiently estab- 

 lished. Thus, among the atrophies of the muscles, we may cite that 

 which is induced by the parasitism of trichiuiw The penetration of 

 these minute worms into the muscular fascicles produces lesions that 

 occasion multi])lication of muscular nuclei and a destruction of the 

 contractile sul)stanco. 



The analogy with the atrophy of muscles is undeniable. The 

 atrophic maladies of glandular apparatuses, such as the liver and the 

 kidneys, are often occasioned by poisoning by alcohol, lead, and other 

 chemical substances or they may be occasioned b}^ some infectious 

 microbic malady. Again, it is this latter cause which often leads 

 to the destruction of the osseous substance. In certain infectious 

 maladies like tubert-ulosis and leprosy the bacilli penetrate into the 

 bones and succeed in forming there infectious foci. These bacilli 

 are, howcA^er, incapable by themselves of dissolving and destroying 

 the osseous substance, but the products that escape from them into 

 the bones exercise an irritating action upon the giant cells Avhich set 

 to Avork to eat aAvaA' the osseous lamella^ impregnated with lime. The 

 tuberculous or leprous agent plays, therefore, only an intermediate 

 part in the atrophy of the skeleton, which is immediately caused, as in 



