222 SUMMARY OF CURRENT RESEARCHES RELATING TO 



Resistance of various Bacteria to Alterations in Osmotic Pres- 

 sure.* — Alfred Guillemard added varying quantities of salts of alkalies 

 and alkaline earths to broth, and observed the influence of the thus 

 altered physical conditions of the culture medium upon the growth of 

 different types of bacteria. In this preliminary notice of his researches 

 he gives a few figures which show that Bacillus megatherium is, of the 

 organisms submitted to experiment, the least tolerant of such changes, 

 whereas Staphylococcus pyogenes possesses relatively high powers of 

 resistance. The organisms of the so-called coli-typhoid group occupy 

 an intermediate position. The author is of opinion that these variations 

 in toleration of such physical conditions are sufficiently constant to afford 

 a useful means of differential diagnosis between, for example, B. Frietl- 

 landeri and B. lactis aerogenes, organisms difficult to distinguish by the 

 methods at present in use. 



Comparative Study of Streptothrix pyogenes and Actinomyces 

 hominis.f — R. Chiarolanza compares the morphological and cultural 

 characters of these organisms, as well as the effects of their inoculation 

 into experimental animals. As regards their cultural characters, he finds 

 that there are many points of similarity between the two types. Both 

 grow well upon agar, forming whitish adhesive colonies, the Streptothrix 

 colonies being as a rule larger. On glycerin-agar, Streptothrix colonies 

 appear dark yellow, sometimes black. Both liquefy gelatin. Neither 

 form produces haemolysis on blood-agar plates. As regards their mor- 

 phological characters, both forms consist of threads of various lengths 

 with true branching. Yacuoles appear in the threads in old cultures. 

 Both forms are Gram-positive. Streptothrix pyogenes is acid-fast, Actino- 

 myces hominis is not ; but acid-fastness in the streptothrices is a variable 

 character, susceptible of modification by passage and other means. So 

 that the value of this as a diagnostic point must not be overestimated. 



Cladothrix stereotropa.J — G. Proca and P. Danila point out that 

 this organism, which is found in syphilitic products, exists in four types : 

 a bacillary form with pseudo-branching ; a Streptothrix form ; a diphthe- 

 roid form ; and a coccobacillary form. Injected into animals (rabbits 

 and mice) it gives rise to abscess or septicaemia. 



Streptobacillus niger gangraense pulmonaris.§— G. Repaci isolated 

 from a gangrenous lung a streptobacillus which has some morphological 

 resemblance to Streptococcus pneumoniae. It is easily stained, and is Gram- 

 positive. It is an essential anaerobe, and grows only at incubation tem- 

 peratures. The growth on sugar-agar consists of small circular colonies, 

 at first opaque, but becoming black in about a fortnight. Fluid media 

 are rendered turbid ; the growth is deposited as a whitish sediment. It 

 does not form gas or indol. It does not attack sugars, but glucose is 

 slightly fermented. The cultures exhale a strong putrefactive odour. It 

 is extremely pathogenic to animals. 



* C.R Soc. Biol. Paris, lxvii. (1909) pp. 538-40. 



t Centralbl. Bakt., lte Abt. Orig., liii. (1910) pp. 1-11. 



j C.R. Soc. Biol. Paris, lxviii. (1910) pp. 190-3 (6 figs.) ; and pp. 79-81. 



§ Tom. cit., pp. 216-18. 



