IIO PHARMACEUTICAL BACTERIOLOGY. 



the average household, and the action of the powder must take place at the 

 ordinary temperature of the home. Thus the time required to curdle the 

 milk will vary. The powder should be kept in a cool or cold, dry place. 

 Of course, a small amount of kefirized milk can be used to curdle any quan- 

 tity of fresh milk without using any of the powder. 



The pharmacist should test the kefir which he is about to use in preparing 

 the powder, in order to be certain that it is active in curdling milk. Like- 

 wise should he test the powder prepared from it. 



The kefir powder above described is similar to, although not identical 

 with, certain microbic lactic-acid ferments found on the market, as the 

 lactone tablets, bacillary tablets, yoghurt tablets, fermenlactyl, lacto-bacilline 

 and others. These are prepared from pure cultures of species of lactic-acid 

 bacilli, dried and formed into tablets with some pulverulent (starch, milk, 

 sugar) base, ready for use. The milk (in quart bottles) is first pasteurized, 

 a pinch of salt is added and two or three tablets are crushed and mixed 

 with the milk. In a day or so the milk is transformed into an acidulous 

 drink, resembling buttermilk somewhat in flavor, though it is not buttermilk, 

 as is generally supposed. 



These tablets have gained in favor within recent years. They deteriorate 

 in time, as already stated, and the time-limit is stamped on each container. 

 Like the kefir, they act more quickly at a temperature of about 25 C. 



As may be readily understood, kefir, lactone, etc., will not produce the 

 characteristic changes in milk to which preservatives have been added; in 

 fact, the failure to produce fermentation is an indication that preservatives 

 are present. 



4. Microbic Pest Exterminators. 



Attempts have been made from time to time to exterminate certain animal 

 pests by inoculating them with some fatal contagious disease of microbic 

 origin. Experiments along this line have been carried on for some time, 

 ever since the causative relationship of microbes and disease was fully estab- 

 lished; but it is only within recent years that extensive practical application 

 was made of the use of a few microbic pest exterminators. One of the first 

 to be used with some success was the chintz-bug exterminator. The chintz- 

 bug (Blissus leucopteris, also called chinch-bug, chink-bug) was a very 

 destructive corn (Zea mays} pest of the Central States (Illinois, Kansas, 

 Nebraska, Iowa), causing great damage to crops during certain very dry 

 seasons. Extensive experiments carried on at the University of Illinois and 

 also at the University of Minnesota (Departments of Agriculture) led to the 

 discovery of a microbic disease of this pest which was quickly fatal and which 

 spread very rapidly. The insects, in cages, were inoculated with pure 

 cultures of the pathogenic microbes, and insects in the diseased condition 



