DIPHTHERIA. 303 



even from the seat of inoculation during the latter stage of 

 the disease ; — another fact that helps to explain LofBer's 

 inability to find the organism in certain of his causes. 



From all this it is concluded that the local symptoms of 

 diphtheria are due to the action of a specific bacillus on a 

 weakened mucous membrane or on a wounded surface ; that 

 once having gained a footing it gives rise to an acute in- 

 flammatory process, probably by the direct action of the 

 poisonous material that it forms on the cells and on the 

 blood vessels in the immediate neighbourhood ; this caustic 

 action is so intense that the epithelial cells undergo de- 

 generation, — the fibrinous lymph and leucocytes which are 

 exuded also become more or less rapidly degenerated — and 

 give rise to the grey false membranous patches that are so 

 characteristic of true diphtheria. When the growth of the 

 organism is rapid, and where the area of surface attacked 

 is extensive, the amount of poison developed may be very 

 ■ great indeed, and where this latter is greater than can be 

 dealt with in the inflammatory area, owing to the rapidity 

 with which it is produced by a large number of organisms, 

 especially when they are situated deep down in the 

 tissues, there is rapid absorption of the poison, but not of 

 the bacilli, into the system, and the characteristic constitu- 

 tional symptoms of the disease are set up. We must thus 

 distinguish carefully between the local action of the bacillus 

 and its products, and the toxic constitutional effects of these 

 products. 



Additional proof that these products are the active agents in 

 the causation of the disease was found in the fact that from 

 pure cultures of the diphtheria bacillus there maybe separated, 

 by means of Chamberland's porcelain filter, a special chemical 

 substance, or series of substances, which, after being proved 

 quite free from bacilli and injected under the skin of animals, 

 gives rise to all the constitutional symptoms and lesions of 

 the disease that follow the inoculation of the bacillus itself, 

 the only feature wanting being the false membrane, which 

 usually does not make its appearance. Animals into which 

 small doses are injected are frequently attacked by diph- 

 theritic paralysis. 



Of course it has been objected that the diphtheria pro- 

 duced in animals is not necessarily the same thing, nor is it 

 necessarily due to the same organism, as the diphtheria of 



