3G0 SUMMARY OF OURUENT RESEARCHES RELATING TO 



those in use by others. Tho principal novelty is the method of 

 transfer. The change that occurs in some nutritive fluids when 

 heated to 110^ C. for several hours led to the adoption of repeated 

 heatings for shorter periods, tho cold sterilization and filtration, the 

 gelatin plan of Koch, and cultivations on solids, as boiled potatoes, 

 Ac. Dr. Ful gives the preference to sterilized beef-broth as used by 

 Dr. Miqucl, but instead of sterilizing the flasks and their contents in 

 boiling salt-water bath or concentrated solution of chloride of sodium, 

 or in a Pa^nn's digester charged with water, which he considers has 

 some advantages, he endeavours to get rid of the risks incurred in 

 the superheating and charging of the empty superheated flasks or 

 tubes, and to obtain a less percentage by loss. 



Dr. Fol never passes the liquid into a fresh receiving vessel 

 except by a sterilized tube made to perforate the plug closing its 

 mouth. Carded, fine, flexible, silky asbestos is preferred for the plug, 

 as being more easily sterilized and perforated than cotton. The 

 decoction of beef is prepared after Dr. Miquel's formula : 1 kilo- 

 gramme of lean beef to 4 litres of water, boiled five hours and skimmed 

 from the first boiling, then cooled, the fat removed on the morrow, 

 and the acidity neutralized by caustic soda. Dr. Fol now filters this 

 through a paper filter into a Papin's digester, kept for one hour at 

 110^ C, then cooled and re-filtered to remove the flaky precipitate. 

 It now remains perfectly clear, is returned to the Papin's digester 

 with its special arrangements, and kept at 110° C. from four to six 

 hours, by which time a notable quantity of peptones are formed in the 

 broth. The longer the boiling, the deeper the tint. The cover of 

 the digester is pierced with three openings ; one retains a copper 

 tube closed beneath for holding the thermometer, a little oil being 

 placed in the tube; the second corresponds to the valve which is 

 loaded for a temperature between 110° and 112° C. ; the third is 

 closed by a pierced cork and screw-nut. Through tho cork is 

 pushed a tight-fitting metal tube, twice bent at right angles to form 

 a siphon, the long leg being inside the digester. This tube is flamed 

 before being put in position ; the short outside leg is terminated by a 

 thick, short caoutchouc tube, into the open end of which a metallic 

 canula is fitted ; this is a trochar tube, into which the steel point of 

 the trochar cut off has been soldered, and just above it an oval aper- 

 ture is made in the tube. This tube is used to pierce the asbestos 

 plugs and to transfer the broth. The ordinary culture flasks have 

 the neck narrowed at one part to keep the plug in position, and with 

 it are sterilized at 200° C. 



The transfer of broth is made by drawing up the long leg of the 

 siphon above described into the vapour space in the digester; a 

 pinch-cock that closed the caoutchouc junction is opened, and the 

 vapour allowed to escape through the canula for ten minutes. The 

 outer surface and point of the canula are now flamed by a Bunsen 

 burner ; then the point is placed in sterilized cotton, the pinch-cock 

 closed, and the tube pushed down nearly close to the bottom of the 

 digester. A little broth is now allowed to escape by the canula, and 

 this is then plunged, the pinch-cock being shut, through the plug of 



