1588 Journal of Applied Microscopy 



producing this haimolytic enzyme develop colonies whicii become surrounded by 

 a clear area, due to the disappearance of the haimoglobin. This enzyme does 

 not appear to be the same as the casein disgesting enzyme, since some bacteria 

 produce the one and not the other. In a similar way he tested the production 

 of an amylolytic enzyme, by bacteria. For this purpose he mixed agar with a 

 small amount of boiled starch, and inoculated and made plates as usual. After 

 the colonies have grown there can be detected around the colonies producing a 

 starch digesting ferment, clear fields where the starch has disappeared, or the 

 presence of the enzyme can be tested by throwing a weak solution of iodine 

 over the plate, when the plate will turn blue in all regions where the starch has 

 remained undigested ; the clear fields around the areas are not rendered blue, 

 indicating that the starch has been converted into sugar. This production of 

 amylolytic ferment is tested for many bacteria. Lastly, he tested the power of 

 micro-organisms for saponifying fat. The method in this case was to mix 

 certain amounts of fat, mutton tallow being used, with the agar under certain 

 conditions, and then inoculating as usual. The bacteria which produce the 

 saponifying enzyme become surrounded by areas in which the appearance of the 

 fat has been greatly changed, due to its saponification. 



The method is quite ingenious, and the experiment interesting and suggestive 

 of further data for determining physiological properties of bacteria, and of thus 

 assisting in separating different species from each other. 



H. W. C. 



Kreibich. Ueber bakterienfrei Eiterung beim It has been generally assumed in 

 Menschen. Wien. klin. Woch. 14 : i;8i, iqoi. , .1 . ,i r • r 



•> -^ ^ recent years that the formation of pus 



was always the result of the action of bacteria, so much so that it has been more 

 or less a dictum of bacteriologists that there is no pus formation without micro- 

 organisms. It has, however, been recently recognized that there are certain 

 chemical agents which are certainly capable of producing pus, totally independ- 

 ent of micro-organisms. For example, Croton oil, turpentine, or nitrate of silver, 

 injected subcutaneously in animals, produce pus without a suspicion of bacterial 

 action. The author studies the question whether pus is ever naturally formed 

 in man in any other way than by the agency of bacteria. That pus may be 

 formed in man by the action of oil of turpentine and other chemicals, is evident ; 

 but the author is quite convinced, from his observations, that there are certain 

 instances when pus is formed naturally in the human body, and yet independent 

 of the action of bacteria. He mentions, for example, some cases of pus forma- 

 tion in bubonic pest, in which the most careful examination has failed to show 

 any trace of micro-organisms. He himself studies some cases of eczema in 

 which pus is formed. The most careful study with the microscope failed to 

 show any organisms in the pus, and the most careful investigation by culture 

 methods has failed to reveal their presence. A long series of studies in this 

 direction convinced him that such pus is sterile, and can not therefore be regarded 

 as due to the action of bacteria. Hence, he concludes that the dictum, no pus 

 without micro-organisms, is totally erroneous, and that sometimes pus is formed 

 naturally in man by chemical action. h. w. c. 



