598 SUMMARY OF CURRENT RESEARCHES RELATING TO 



fever. At the autopsy a paracolon bacillus only was isolated from the 

 spleen, and no lesions such as are usually associated with infection by 

 the B. typhosus could be demonstrated. The bacillus presented the 

 following characteristics : — motile, decolorised by Gram ; surface colonies 

 on gelatin plates resembled those of the B. typhosus or delicate colon 

 colonies ; agar streak, moderately heavy growth ; broth, uniform tur- 

 bidity at first, later a sediment is deposited and sometimes pellicle 

 formation is observed, no indol is formed ; litmus milk after 14-24 

 hours becomes reddened, after 48 hours has again become blue, and 

 later still the colour of the litmus may be completely discharged. 

 Glucose and saccharose are fermented by the bacillus in the course of 

 its growth, but not lactose. Unfortunately no blood was collected at, 

 the autopsy, so there was no opportunity of testing for the presence of 

 agglutinins. The bacillus was pathogenic for mice in doses of 0-5 ccm. 

 ■( ? broth culture) and was recovered post-mortem from the blood and 

 organs. This makes the fourth recorded case of primary infection by 

 paracolon bacilli. 



Differential Diagnosis of Coli and Typhoid.* — Wolff eulogises the 

 neutral red method of differentiating the B. typhosus from the B. coli 

 ■communis, and definitely states that it never fails. He points out that 

 when grown in neutral-red agar plate cultivations, the colonies of the 

 typhoid and colon bacillus become coloured, due to vital staining of the 

 individuals of which they are composed. If such bacilli are examined 

 in water they are seen to be motile, but the stain is quickly washed out, 

 but if examined in weak neutral-red solution the preparation appears to 

 consist of cocci, not bacilli, owing to the presence of one or two neutral- 

 red spots visible in each bacillus, although the motility is not affected. 



The author also discusses whether or no the B. typhi abdominalis can 

 assume a pyogenic role, and whilst not giving a decided opinion inclines 

 to the belief that under certain conditions it may do so. 



Unity of Pathogenic Streptococci.! — Marmorek, after critically 

 studying 42 strains, maintains the unity of streptococci pathogenic to 

 man, and disregarding minor morphological differences — referable to 

 variations in environment or the composition of nutrient media, symbi- 

 otic life or the like — points out that several vital characteristics are 

 common to all, no matter what their source. 



The first of these is the power possessed by the virulent strepto- 

 coccus of hasmolysing the blood of the rabbit in vivo, a character which 

 constitutes a direct index of the virulence of the streptococcus ; the 

 second, its inability to grow in filtered cultivations of the same or other 

 virulent streptococci ; and finally, all pathogenic streptococci from what- 

 ever source agree in that they are capable of being exalted in virulence 

 to a definite fixed standard. 



The author further states that the streptococci isolated from scarle; 

 fever anginas possess but slight hemolytic powers, which, moreover, are 

 not increased by exalting the virulence of the organism, and are als > 

 able to develop to a certain extent in filtered cultures. These, however, 

 are merely differences of degree aud not of kind. 



* Centralbl. Bakt.. l te Abt., xxxi. (1902) pp. 69-72. 

 t Ann. lust. Pasteur, xvi. (19i>2j pp. 172 8. 



