92 SUMMARY OF CURRENT RESEARCHES RELATING TO 



that the general acceptance of a specific organism of dysentery seems 

 unavoidable. 



Melanogenic Variety of Bacillus pyocyaneus. * — C. Gessard, 

 after alluding to Cassin's discovery of a variety of Bacillus pyocyaneus, 

 which in certain media produced a red, and finally a black pigment, 

 shows that the principal factors in the production of the pigment are 

 the presence of tyrosin in the medium and the existence of tyrosinase 

 in the microbe. The bacterium uses another diastase, trypsin, to bring 

 the tyrosin into a condition suitable for the action of the tyrosinase. 

 It can attack tyrosin in combination and in the free state, and thus may 

 be compared to Millon's reagent. 



Biochemical Studies on the Tubercle Bacillus, f — Elementary 

 analysis of tubercle bacilli cultivated on different media was found by 

 r. A. Levene to give widely different results, especially in the amount 

 of alcohol-ether extract. Differences were also observed in the amounts 

 of proteid and of free nucleic acid present. By fractional heat-coagula- 

 tion the proteid material can be separated into three substances, each of 

 which contains phosphorus. The nucleic acids separated vary much in 

 ■composition ; some of the preparations made are looked on as purer 

 than tbe others. The only carbohydrate studied was one which closely 

 xesembles glycogen ; this appears to be always present. 



Human and Bovine Tuberculosis. J — Prof. S. Delepine, in a pre- 

 liminary communication on the communicability of human tuberculosis 

 to cattle, relates the results of four experiments on calves. The animals 

 were inoculated with a mixture of several tuberculous sputa, repre- 

 senting several types of human tuberculous sputa. Of these four 

 calves two survived long enough to allow definite results to be obtained, 

 and showed that tuberculosis had been contracted as the result of inges- 

 tion of a peritoneal infection with human tuberculous sputa. 



Virulence of Bovine and Human Tubercle Bacilli. § — Dr. M. P. 

 Eavenel records some important experiments and observations which he 

 has made on the comparative virulence of tbe tubercle bacillus derived 

 from human and bovine sources. From these he draws, among others, 

 the following conclusions : — The bovine bacillus has in culture fairly 

 constant and persistent peculiarities of growth and morphology, by 

 which it may be tentatively differentiated from that ordinarily found in 

 man. The cultures from the two sources differ markedly in pathogenic 

 power, affording further means of differentiation ; the bovine bacillus 

 being much more active than the human for all 6pecies of experimental 

 animals treated, with the possible exception of swine, which are highly 

 susceptible to both. It is a fair assumption from tbe evidence at hand 

 and in the absence of evidence to the contrary, that the bovine tubercle 

 bacillus has a high degree of pathogenic power for man also, which is 

 especially manifest in the early years of life. 



Variability of Gas-formation by Bacillus coli communis. || — J. 

 ltoth finds that the power of B. coli communis to ferment grape-sugar is 



* Ann. Inst. Pasteur, xv. (1901) pp. 817-31. 



t Journ. Med. Research, vi. (1901) pp. 135-41. See Journ. Chera. Soc, lxxx. 

 <1901) Abstr. ii. p. 675. J Brit. Med. Journ., 1901, ii. pp. 1224-G. 



§ Lancet, 1901. ii. pp. 349-56, 413-8. 

 || Inaug. Diss. Heidelberg. See Dot. Centralis., lxxxviii. (1901) 



