SFORE-FORMING PATHOGENIC ORGANISMS 87 



the mortality considerably in experimental animals 

 (Kenneth Taylor, Lancet, September 4, 1915). The same 

 organism has been found in the expectorated matter 

 from cases of pulmonary gangrene supervening after in- 

 halation of the irritant gases employed by the Germans (De 

 la Riviere and Leclercq, Medical Press, October 20, 1915). 

 Detection in Water. B. Welchii is regarded as of less 

 importance as an index of pollution in water than for- 

 merly. Large quantities of water must be examined, and 

 it was previously the custom to pass half a litre through 

 a Pasteur- Chamberland candle, suspend the deposit in 

 5 c.c. of sterile water, and inoculate three milk tubes with 

 3 c.c., 1 c.c., and 1 c.c. respectively of the concentrated 

 water. The milk tubes were then treated as described 

 below. Hewlett's method of conducting the test, though 

 cumbersome, is more satisfactory. Ten large boiling 

 tubes, each containing 50 c.c. of sterile milk, are inoculated 

 each with 50 c.c. of the water, melted vaseline is poured 

 on the surface of the mixture to exclude air, and each 

 tube is covered with a double layer of sterile filter-paper, 

 kept in position by a rubber band. The tubes are heated 

 in a bath of water to 80 C. for twenty minutes, and 

 incubated at 37 C. for two days. When smaller amounts, 

 such as 10 c.c. of liquid, are to be examined, an exposure 

 to 80 C. of ten minutes is sufficient. The gas produced 

 in the fermentation (vide supra) collects as a bubble under 

 the vaseline plug. The Closlridium butyricum (which is 

 principally responsible for the butyric fermentation of 

 milk, and which, when present, hastens the production 

 of tyrotoxicon therein) gives a similar reaction in milk, 

 but is not pathogenic for guinea-pigs. The only way to 

 distinguish B. Welchii from Clostridium butyricum, which 

 is regarded by some as a non- pathogenic form of the 

 former, is to inject 2 c.c. of the whey subcutaneously 

 into a guinea-pig of about 200 grammes weight, when 

 B. Welchii will kill the animal in forty-eight hours. 



To isolate B. Welchii from pus, Alexander Fleming 

 (Lancet, August 21, 1915) recommends the following pro- 

 cedure: A tube of sterile milk is boiled and immediately, 

 while yet at a temperature close to 100 C., is planted 

 with some of the pus. The scum of cream suffices to 

 exclude air. If other spores get in, anaerobic plate 

 cultures on glucose agar are made. 



