484 THE AUTOGENOUS DISEASES. 



fact which has been illustrated specifically in the preceding chapter, 

 that among the metabolic products of the animal body there are to 

 be found substances which are more or less toxic in their action. 

 By the word autogen,(ms, as indicating a class of diseases, we under- 

 stand that in these disorders the materies morbi is a product of some 

 cell of the body, and not, as in the case of the infectious diseases, of 

 cells introduced from without the body. Much has been said about 

 auto-intoxication, and in our opinion a large part of what has been 

 said upon this subject is without sufficient scientific foundation. 

 Auto-intoxication is a word now frequently used to cover up our 

 ignorance, and the time has not yet come for a thorough investiga- 

 tion of this subject. Indeed, it is almost impossible in a given case 

 to exclude external factors which influence diseased conditions. 

 While we must admit that poisons are formed in the animal body, 

 it is not always easy — in fact we may say it is never easy — to be 

 certain that the starting point does not lie outside the body. Some 

 writers have mistaken the secondary effects of ectogenous toxins for 

 auto-intoxications. As an illustration of this we may mention the 

 attempt that has been made to classify alcoholic cirrhosis under the 

 head of auto-intoxications. The explanation which has been offered 

 by those who have advocated this classification is that the changes in 

 the liver are not due to the direct action of alcohol, but that as a re- 

 sult of the abuse of this beverage a diseased stomach results, and on 

 account of its diseased condition permits the absorption of imper- 

 fectly digested substances, to the direct action of which the changes 

 in the liver and other organs are to be attributed. According to 

 our way of looking at it, alcoholic cirrhosis is due either directly or 

 indirectly to the action of the toxic substance which is introduced 

 from without, and certainly should not be classed among autogenous 

 diseases. Auto-infection has also been confounded with auto-intoxi- 

 cation. 



These two processes are wholly distinct, and a clear comprehension 

 of each will prevent confusion. The term auto-infection is properly 

 applied to those cases in which the virus of disease is carried locally 

 in some part of the body, and is distributed from this locality to 

 other parts of the body. Illustrations of auto-infection are numerous 

 in certain diseases, and especially in tuberculosis. An individual 

 with pulmonary tuberculosis swallows his sputum and infects his 

 intestinal walls. Another person may carry for years a colony of 

 tubercle bacilli in his lungs, in his bones, or in some other part ot 

 his anatomy, and then when this individual is exposed to conditions 

 which materially lower his vitality, the bacilli which have been con- 

 fined to a narrow locality, pass beyond the bounds to which they 

 have so far l)een restricted, and invade every tissue, leading to acute 

 miliary tuberculosis. Post-mortem examinations have shown that 

 one-third or more of all men have latent tuberculosis, and this un- 



