EELATION OF PATHOGENIC TO SEPTIC BACTERIA. 25 



several organisms begin to grow, you will justly say that all 

 these organisms are accidental contaminations, air organisms-; 

 but if you found in the streak one species or more growing 

 you cannot conclude from this that you have transferred this 

 or these species from your original material, because your moist 

 needle-point or capillary glass tube may have caught these seeds 

 while passing through the air ; and this has actually happened 

 to me, not once, but repeatedly. 1 have several instances in 

 which I have sown or meant to have sown in one streak over 

 the gelatine drop of my cell specimen a particular species of 

 bacillus, and to my great annoyance I found, after several days' 

 incubation, in that very streak growing three different species 

 of organisms, viz. one kind of micrococcus and two different 

 species of bacilli. In another instance I wished to test a fluid 

 for the presence of an organism or organisms, consequently I 

 sowed it out on the gelatine in several of my glass cells, and I 

 obtained in the streak drawn over the gelatine drop two species 

 of organisms, a micrococcus and a bacillus ; but as I ascertained 

 with a more precise method, the fluid contained no organism 

 whatever. These facts, it must be conceded, prove that the 

 method of Koch, although of great value in certain cases, is 

 less to be recommended in others, and therefore does not deserve 

 that unqualified praise which its author accords to it (1. c), say- 

 ing as much as that this is the only method after which cul- 

 tivations of micro-organisms are to be carried on. I shall 

 presently show that there is a more reliable method (provided 

 the question is one of transferring one definite organism from 

 one fluid into a vessel containing the nourishing material), a 

 method in which the chances of contamination are less and the 

 method also, for other reasons more practicable. 



The method of inoculation of the nourishing material which 

 I at first used was under the protection of the carbolic-acid 

 spray: a freshly drawn out capillary pipette is dipped into 

 the material to be sown, the cotton-wool plug of the test- 

 tube or flask containing the nourishing material is lifted under 

 carbolic-acid spray on one side just suflicient to admit the end 

 of the capillary pipette; this being done the plug is again closed 



