200 BACTERIOLOGICAL METHODS 



medium or by displacing the air by means of the hydrogen ap- 

 paratus. The colonies which appear should be examined micro- 

 scopically to ascertain whether or not the characteristic spore- 

 forming tetanus bacillus (drum stick bacillus, the Trommelschlager 

 Bacillus of the Germans) is present. As a confirmatory test, a 

 suspension of the suspected colony should be injected hypo- 

 dermically into guinea-pigs or white rats and symptoms noted. 

 Should other than the spore-forming bacteria be present in the 

 anaerobic culture, these may be killed by pasteurizing for i hr. at 

 80° C, at which temperature all organisms excepting the spores 

 of the tetanus bacilli are killed. Again incubate at 37° C. for 

 several days and examine microscopically, and make inocula- 

 tion tests as already suggested. The finding of a single tetanus 

 bacillus (as represented by a single colony in the anaerobic culture) 

 in the gelatin renders it unfit for use. 



To test medicinal substances of all kinds in powdered form, 

 the plating method must be relied on very largely, as the bacteria 

 which might be present would be hidden or obscured by the 

 granular particles present. However, extensive yeast and mold 

 contamination could be detected readily and estimated quantita- 

 tively by the direct microscopical method. The qualitative 

 test for this class of substances is very largely Hmited to the 

 determination of the absence or presence of the colon group, 

 the staphylococcus group and the streptococcus group. Face 

 powders and dusting powders should be free from any consid- 

 erable contamination with the pus-forming organisms. There 

 should be uniformly standard methods governing the manu- 

 facture of all medicamenta, intended for internal or external use, 

 which must be touched by the hands of the manufacturer. There 

 must be absence of all skin diseases and of transmissible conta- 

 gions of all kinds. There should be specific requirements as to 

 personal cleanliness and the sanitation of the laboratory. Just 

 as typhoid carriers, cholera carriers and diphtheria carriers em- 

 ployed as servants in the household and as laborers in the factory 



