ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 87 



Diagnosis of Bacteria by their Biochemical Functions.* — 

 L. Grimbert says that the fermentative activity of a micro-organism 

 is its most constant property, and a knowledge of biochemical function 

 is extremely important for determining species. The practical rule is 

 that each form which assumes another constant function deserves a new 

 name ; cultural characters are only of secondary importance. 



The choice of media is important ; owing to complicated composition 

 (defying chemical analysis) uniformity is impossible. Glucose in 

 bouillon is the chief cause of alkali or acid production. Pepton after 

 48 hours inoculation with B. coli should give the indol reaction, and it 

 ought not to be mixed with nitrogenous substances (hence peptonised 

 bouillon is excluded) or carbohydrates or nitrates. The choice of ferment- 

 able media is to be restricted to the simplest and most characteristic 

 substances, e.g., coagulated albumen for trypsin production, milk as a 

 coagulation index, pepton for indol reaction, urine for production of 

 ammonium carbonate by urobacteria of Miguel, nitrates to distinguish 

 true denitrification ferments {Bacillus pyocyaneus liberates nitrogen from 

 pepton solution) from indirect denitrificators, which only work in amido- 

 containing media, e.g. bouillon. The best medium for this is pure 

 potassium nitrate 1 part, pepton 1 part, distilled water 100 parts. 

 Carbohydrates are valuable if chemically pure, and should be mixed with 

 pepton. Solid media, the reaction of which is never constant, are not 

 to be used. Fluid media are to be neutralised with calcium carbonate. 



The plan of research includes general biology and morphology, 

 cultural characteristics in various media, biochemical characters, agglu- 

 tination phenomena, and animal inoculation. 



From personal biochemical research he discusses finally : — 



1. Bacillus orthobutylic us and its differentiation from other anaerobic 

 butyric acid ferments. 



2. Friedlander's pneumobacillus which acts energetically on glycerin 

 and dulcitol, producing in certain cases laevo-lactic acid. Two groups 

 of this bacillus are distinguished, viz. : Frankland's bacillus, with no 

 action on glycerin and dulcitol, and Grimbert's bacillus, one variety 

 of which attacks glycerin and dulcitol, the other glycerin alone ; both 

 groups with mannite give lsevo-lactic acid. 



3. Identity of Friedlander's bacillus with B. lactis aerogenes. Cha- 

 racters common to both are — immobility, presence of capsules, non- 

 liquefaction of gelatin, no indol formation, and energetic action on 

 carbohydrates. 



4. B. tartar icus (Grimbert 181)7) and its energetic action on tartrates 

 and carbohydrates (producing acetyl-methyl-carbinol). 



5. The action of B. coli and typhosus on nitrates, which are only 

 indirect denitrificators, working only in the presence of amido com- 

 pounds. 



Differentiation and Identification of Streptococci and Staphylo- 

 cocci.! — M. H. Gordon reports the results of his observations on a large 

 number of streptococci obtained from various sources, particularly as 



* Archiv de Parasitol., vii. pp. 237-305. See also Centralbl. Bakt., l*e Abt. 

 Eef., xxxvii. (1905) pp. 263-5. 



f Local Gov. Board Supp. Medical Officer's Rep., 1903-4, p. 388. 



