198 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
bacteria, and for the first 4 to 8 days, of diastase. Later on, however, the 
medium was liquefied, bacteria being still absent. These facts indicate 
the utility of the bacterial secretions in assisting digestion ; and this view 
is confirmed by the absence of microbes in the dejecta of fowls brought 
up in the ordinary way during the first 36 or 40 hours ; for during this 
period they scarcely increase in weight. 
Number of Micro-organisms in Air, Water, and Milk, as de- 
termined by their Growth in Different Media.* * * § — Mr. A. W. Bitting 
shows, by experiments made with agar, glvcerin-agar, beef-gelatin, and 
wort-gelatin, that the number of organisms in air, water, and milk vary 
with the medium, agar showing the highest number of bacteria, and 
wort-gelatin the highest number of moulds. Hence it is important to 
indicate the medium used, and how it is prepared, as well as the number 
of microbes found. 
Necessity of Xylose to Denitrifying Bacteria.j — In a preliminary 
communication, Prof. J. Stoklasa states that he regards pentose xylose, 
C 6 H 10 O 5 , which is derived by hydrolysis from pentosan xylan, as the 
most suitable and most natural nutriment for denitrifying bacteria. 
This conclusion was arrived at from observing that denitrification was 
greatest in media containing xylose, as contrasted with arabinose, glu- 
cose, fructose, and saccharose. The denitrifying bacteria used were 
Bacillus megatherium (B. Ellenhachii a), B. denitrificans, B. subtilis, and 
B. fluorescens liquefaciens. 
The Bacterial Capsule.^ — Hr. R. Binaglii records his endeavours to 
demonstrate a capsule in streptococci derived from six different sources. 
No trace of a capsule was discoverable in any of the instances. After 
referring to Str. capsulatus, the author alludes to 28 capsule bacilli, the 
enumeration of which may be found useful to those interested in the 
subject. He concludes from his observations that (1) as a rule, strepto- 
cocci are devoid of capsules ; (2) that when bacteria are provided with 
a capsule, this is always to be found in the natural medium, and fre- 
quently in artificial ; (3) the capsule is to be regarded as the swollen 
outer layer of the bacterial membrane which comes into existence owing 
to the biochemical activity of the bacterium within the organism. 
Capsule Bacilli and their Differentiation^— Dr. L. W. Strong thus 
summarises the distinction between two groups of capsule bacilli. In 
the first, or Friedlander group, are included B. pneumoniae Friedlander, 
B. ozaenae Fasching, B. sputigenus crassus or mucosus capsulatus, B. 
Wright and Mallory , and perhaps B. rhinoscleromae. 
The young colonies are colourless, but become white with age. The 
capsules of the organisms taken from the animal body are easily stained ; 
on artificial media there are only pseudo-capsules. Gas formation is very 
copious when the medium contains cane-sugar, less so with grape-sugar, 
and little or not at all with milk-sugar. There is no formation of acid 
in milk-sugar bouillon, and milk is not coagulated. 
* Proc. Indiana Acad. Sci., 1897, pp. 143-1. 
f Centralbl. Bakt. u. Par., 2 te Abt., iv. (1898) pp. S17-9. 
t Tom. cit., pp. 897-902, 919-24. Cf. this Journal, 1897, p. 577. 
§ Op. cit., l te Abt., xxv. (1899) pp. 49-52. 
