824 SUMMARY OF CURRENT RESEARCHES RELATING TO 



and pporc-fomiatioD, the dyes previously racntioned are of little value, 

 but pliloxiu-red may be employed with advantage. It is extremely 

 soluble in water, stains spores quite intensely, and cultivations on 

 gelatin and bouillon stained with this dye throve luxuriantly. Experi- 

 ments on typhoid bacillus made by this method con6rmcd the formation of 

 spores as first stated by Gatfky. Benzo-purpurin was also found to be 

 a useful dye, as it stained the spores alone, and left the rest of the proto- 

 plasm uncoloured. , 



Cultivation of Anaerobic Micro-org-anisms.* — Dr. C. Friinkcl has 

 invented an apparatus for the cultivation of anaerobic microbes, which 

 he says combines the advantages of the methods of Liborius and Griiber. 

 The nutrient media, bouillon, gelatin, agar, are placed in test-tubes 

 somewhat wider than the ordinary ones. Sterilization, inoculation, &c., 

 are then performed in the usual way. This done, the tube is closed 

 with a caoutchouc ping, through which pass two glass tubes bent at a 

 right angle. One of these reaches to the bottom of the test-tube, the 

 shorter one goes no farther than the bottom of the caontchouc plug. 

 The exposed extremities are drawn out to fine points, and this arm of the 

 longer tube, besides containing a plug of cotton-wool, is connected with 

 a hydrogen apparatus by means of a piece of rubber tubing. The gas 

 then passes through the nutrient medium and escapes through the 

 shorter leg. When the air is thoroughly expelled, the pointed ends are 

 melted up, and then the medium is spread over the surface of the test- 

 tube in the manner proposed by Ehrlich. 



In order to prevent certain sources of error, two points must be 

 rigorously observed ; first, the tw'o pieces of glass tubing and the rubber 

 plug must be thoroughly sterilized. This is best done by laying them 

 for an hour in a 1 per cent, sublimate solution. The second source of 

 error is the escape of the hydrogen and the entrance of air. This is 

 avoided by covering the plug with paraffin which melts at about 80^. 



"When bouillon is the medium, the test-tube can be freed from every 

 trace of air in 1^-2 minutes. 



If gelatin be used, then the test-tube miist be placed in water at 

 37° while the gas is passing through. This takes only 3-4 minutes. 

 Agar must be used in 2 per cent, solution to which 1 per cent, grape 

 sugar is added. As the agar solidifies rapidly below 40^, it is necessary 

 to be quick in passing the gas through and wetting off the points. The 

 tube must then be rolled round in lukewarm water or in the hand. 



The advantages claimed for tliis method are cheapness, convenience, 

 and suitability for its intended purpose. 



Bacterial Growth between 50° and 70° C.f — Dr. Globig who has 

 been exi>erimenting with Bacteria found in garden mould, made his 

 preliminary isolation in covered capsules of 5-7 cm. diameter, and 

 grew the micro-organisms on pieces of potato. The colonies thus 

 obtained were cultivated in test-tubes on blocks of potato cut obliquely. 

 For the latter step, potatoes were boiled and disinfected with sublimate 

 solution, and then cylindrical blocks punched out of them with a cork- 

 borer, the diameter of which was just less than that of the test-tubes. 

 The blocks were then cut obliquely, and jammed in the test-tubes so 

 that they did not move, and closed with the usual precautions. By this 



♦ Ccntralbl. f. Bakteriol. u. Parasitenk., iii. (1888) pp. 735-40, 763-8 (1 fig.)- 

 t Zeitachr. f. Hygeine, iii. (18s7) p. 295. 



