32 CLINICAL BACTERIOLOGY. 



specific bacterial poisons, to be the same in many or in all 

 bacteria ; at least, their action is not specific. They never 

 give rise to the typical clinical picture that is characteristic 

 of the bacteria from which they are obtained, but they 

 always give rise to fever and leukocytosis only, and, on 

 subcutaneous injection, to local inflammation and suppura- 

 tion besides. For the white blood-corpuscles they possess 

 especially a most marked attractive influence, being with 

 regard to them positively chemotactic. Administered in 

 large amounts the bacterial proteids cause the death of the 

 animal ; but even then the course of the disease presents 

 nothing characteristic, and not more so the postmortem 

 findings. Detailed reference to the latter will be made in 

 the consideration of tuberculin (see Tuberculosis), which, 

 like mallein (see Glanders), is a proteid. 



Chemically, these bacterial proteids approach the vege- 

 table caseins. Treated with basic aniline dyes, they lose 

 their toxic activity, and they may be considered as that 

 constituent of the bacterial cell that confers upon it the 

 property of taking up stains. The bacterial proteids are 

 soluble in dilute alkalies, and insoluble, on the other hand, 

 in dilute acids. They are best prepared by adding to a 

 bouillon-culture in as large amount as possible bacterial 

 scrapings from solid culture-media, and boiling the mixture 

 for about two hours, then evaporating down to one -fifth or 

 one-fourth, and filtering through porcelain. From the 

 filtrate the proteid substances are precipitated by the addi- 

 tion of ten times their volume of absolute alcohol. They 

 form an amorphous powder that is readily soluble in water. 

 Besides, the filtrate of unboiled old bouillon-cultures gener- 

 ally contains a certain amount of proteid substances that 

 have gradually found their wa^ out of the bodies of the 

 numerous dead bacteria into the fluid. 



E. Buchner has recently devised a procedure for the 

 preparation of unchanged cell-fluid. The cells are rubbed 

 up mechanically and exposed to a pressure of from four 

 to five hundred atmospheres. Buchner obtained in this 

 way from yeast-cells a fluid of yellow color and alkaline 

 reaction that yielded ten per cent, of solid constituents, 

 and an abundance of albuminous bodies precipitable by 

 heat. This so-called yeast-cell expressed fluid no longer 

 contained living germs, although it still was capable of in- 

 ducing alcoholic fermentation. H. Buchner considers the 



