SUPPURATION. 85 



jection of various substances. For instance, paralactic acid was 

 found to act similarly to tuberculin and on section of tubercular 

 animals treated with this agent the diseased areas were observed to 

 be hyperemic and to contain hemorrhagic spots. Matthes ascertained 

 that certain albumoses and peptons affect tubercular animals in much 

 the same way, though to a less degree, as tuberculin does. 



There has been some question among pathologists concerning the 

 manner in which tuberculin acts on tubercular tissue, and in this 

 connection Baumgarten makes a statement which may be condensed 

 as follows : It causes an exudative inflammation in the vascular 

 tissue about the tubercle, and in this way the tuberculous tissue may 

 be isolated and, when situated superficially, removed. In some 

 cases, however, after the prolonged employment of the agent, the 

 tuberculous tissue may, under the influence of the exudative fluid 

 and the polynuclear leucocytes, break down and form abscesses. 

 The bacilli themselves are in no case harmed by the use of tuber- 

 culin, and, after its constant employment for months, they retain their 

 original form and lose none of their virulence. Some preparations 

 seem to show that the bacilli multiply more rapidly when the injec- 

 tions are made, but a positive statement on this point is reserved until 

 further studies have been made. It is certain, however, that the 

 non-tubercular tissue of animals acquires no immunity against the 

 disease from the injections. This is shown by the appearance of 

 metastatic foci in animals in which from 7 to 12 grams of the orig- 

 inal lymph (an amount which would be equivalent to from 70 to 180 

 grams in man) have been injected. It is further shown by the fact 

 that in some animals treated subcutaneously tubercles have appeared 

 at the point of injection. 



Suppuration. — As early as 1879, Leber concluded from his ob- 

 servations on infective keratitis, that the aspergillus must produce 

 certain soluble products which difluse through the cornea and set up 

 an inflammation in the adjacent vascular tissue. In 1882 he showed 

 that suppuration could be induced by the introduction of sterilized 

 mercury and copper, and that the pus formed is free from microor- 

 ganisms. In 1884 he induced suppuration by the injection of cul- 

 tures of the staphylococcus pyogenes aureus that had been sterilized 

 by being boiled for hours. In 1888 he reported that he had found 

 an alcoholic extract of the dried staphylococcus to be highly pyoge- 

 netic, and from this extract he prepared a crystalline body which he 

 calls " phlogosin." This substance is readily soluble in alcohol and 

 ether, sparingly soluble in water, and crystallizes in needles. The 

 crystals can be sublimed, leaving no residue, and the sublimate, which 

 forms in rosettes, still possesses pyogenetic properties. Alkalis pre- 

 cipitate this substance from its solutions in amorphous granules, 

 which dissolve in acids, forming crystalline salts. 



