136 



recover}' may more or less be expected. Or it may be 

 fouud as a part of a more extensive septicaemia, as is 

 well known both to practitioners of human and 

 veterinary medicine. In this latter case it is manifestly 

 of an even more virulent and fatal nature than in the 

 former, since not only is a larger area of the lungs 

 usually invaded, but the vital powers of the patient 

 are necessarily overwhelmed b}' the general blood 

 poisoning. 



In the older days of medicine, those anterior to 

 the understanding of the important part played by 

 micro-organisms in the production of disease, pneu- 

 monia was said to be caused by chill alone. It was 

 supposed that the sudden deprivation of the surface 

 blood vessels of their blood, through the constricting 

 effects of cold, caused an immediate rush of blood 

 to the inward parts, and that this state of affairs it- 

 self constituted the inflammation. Then came the 

 era of bacteriological discoveries, and this theory 

 was discarded by reason of the new - found know- 

 ledge of the universal association of certain bacteria 

 with the disease. But with the very proper discard- 

 ing of this theory of the vianner of the production 

 of pneumonia there arose in many minds, medical as 

 well as la3% an unfortunate disassociation of chill as 

 a factor in its causation. As a matter of fact chill 

 often has a good deal to do with the causation not 

 only of pneumonia but a good man}' other diseases 

 of which the immediate cause is a microbe. Patho- 

 genetic organisms, i.e. those which produce disease, 

 are alwa}'s with us in a more or less virulent con- 

 dition. For instance that of pneumonia has been 

 over and over agjain isolated from the mouth secre- 



