22 DE. E. KLEIX. 



As I mentioned above, I charge my test-tubes rapidly either 

 with pure pork broth or with liquefied gelatine pork without 

 spray, and then boil them well for a few minutes, and doing 

 this in the laboratory of the Brown Institution I find it sufficient 

 to thoroughly sterilise the fluids. 



In connection with this subject I would draw the attention 

 of the reader to the very important investigation made by Mr. 

 Watson Cheyne {' Transact, of the Pathol. Society of London,' 

 1879, p. 577) on the value of the carbolic-acid spray in the 

 inoculation of artificial cultures. 



The plan of Koch of spreading out a large drop or small 

 quantity of liquefied gelatine nourishing fluid on a glass slide, 

 or on a flat glass dish, and having inoculated this on its surface 

 with the desired organism to place it in a chamber closed by a 

 bell-jar or the like, which is kept moist by putting into it (the 

 chamber) moist filter paper, has not been found practicable, 

 owing to the fact that the gelatine nourishing fluid having 

 solidified again dries up too soon, before the sown organisms 

 have had time to make a start, the moisture all settling on the 

 inner surface of the bell-jar. This condition I have invariably 

 found to obtain, even when the chamber was closed air-tight, 

 the bell-jar with ground margin being fixed by lard or oil on 

 to a ground-glass plate. Not only in ordinary temperature, but 

 still more so in the incubator, was this drying up of the gela- 

 tine nourishing fluid found to happen, and I have therefore 

 modified Koch's plan by using the arrangement mentioned 

 before, viz. the closed glass cells, and the test-tubes plugged 

 with cotton wool. 



The next important step in the cultivation of bacteria in the 

 nourishing material hitherto described, as contained in the test- 

 tubes or glass cells, is the inoculation of these materials with 

 the organisms it is desired to grow, i. e. the process of sowing. 

 It is, of course, obvious that if it is desired to cultivate a single 

 species of organism, it is necessary to sow a single species, and 

 to prevent contamination with air organisms, the nourishing 

 fluid itself being sterile. With reference to the first, it is 

 necessary to be certain that the material containing the seed 



