952 SUMMARY OF CURRENT RESEARCHES RELATING TO 



immediate and immense advances in our knowledge of the whole 

 series of phenomena to which the Bacteria are related. 



" Amongst problems which require immediate investigation by the 

 new method are the distinctive properties of the various kinds of 

 Bacteria which may infest the wounds of surgical practice, and their 

 specific susceptibility to the destructive influence of carbolic acid and 

 other antiseptics ; further, the possibility of isolating a specific Bac- 

 terium in contagious diseases not yet investigated ; and (of great 

 physiological interest) the isolation and investigation of the properties 

 of the specific Bacterium of the ammoniacal fermentation of urine." 



A remarkable negative result obtained by Dr. Koch, so far as his 

 experiments with the new method of monosporous culture have yet 

 extended, is, that there is no transition of forms amongst, at any rate, 

 the pathogenous Bacteria — a Micrococcus produces Micrococci, and no 

 other form ; a Bacillus produces only Bacilli ; a biscuit-shaped form 

 (Bacterium proper) only biscuit-shaped forms; a Spirillum only 

 Spirilla. Moreover, the fades of the discoidal or spherical mass 

 formed by a growth, as seen with a low power, excavating its way ia 

 the gelatine, is characteristic of species, so that a practised observer 

 can in some cases recognize a particular Bacillus or Micrococcus by the 

 naked-eye appearance of the growth alone, or, at any rate, without 

 actually observing the individual units of the growth. 



Sterilization of Animal and Vegetable Liquids.* — Pasteur has 

 proposed to render sterile liquids infested with Bacteria by filtration 

 through plaster of Paris, and ]\IM. P. Miquel and L. Benoist have 

 devised a simple method for working out this process. The neck of 

 a flask is di-awn out, and the part above the contraction is sealed by a 

 plug of plaster of Paris and asbestos, and immediately below the con- 

 traction a fine capillary tube is drawn out at the side. The apparatus 

 is then dried for a week or two at 40' C, and finally heated to 170°, in 

 order completely to destroy the germs on the sides of the flask and 

 on the plug. When the flask is cooling, the capillary point is intro- 

 duced under perfectly sterilized water, and on breaking it off, 40-50 c.c. 

 of water pass up into the flask. The liquid is then boiled to expel the 

 air completely from the flask, and the poiat is resealed, while at the 

 same time the plug is introduced into the infested liquid. On 

 cooling, the liquid passes into and fills the flask. The authors draw 

 attention to various precautions which are necessary to ensure success. 



Hardening the Spinal Cord-f — The following method of harden- 

 ing the spinal cord for microscopic sections has been highly recom- 

 mended by Dr. M. Debove : — 



Place the cord in a 4 per cent, solution of bichromate of ammonia 

 for three weeks, then in a solution of phenic gum for three days and 

 for three days more in alcohol. Sections may then be cut with 

 great facility. They should be placed in water to prevent curling. 

 They are then immersed in a saturated solution of picric acid for 



* Bull. Soc. Chim., xxxv. (1881) pp. 552-7. See Joum. Chem. Soc. (Abstr.), 

 xl. (1881) p. 835. 



t Archives de Neurologic. See Science, ii. (1881) p. 482. 



