ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 341 



typhus bacilli and Bacterium coli remained living for the longest time. 

 The conclusion is that the oil should be sterilised and that the catheter 

 should never be placed in oil but some of the latter removed for the 

 purpose ; the catheter should then be sterilised from time to time in the 

 water-bath. 



Bacteria in Pus from a Gas-containing Abscess.* — Rodella has 

 investigated the pus from such an abscess and finds besides a Streptococcus 

 and an organism belonging to the coli group, two anaerobic rod-like 

 forms which are further described, one having the power of gas- 

 formation. 



Pigment Bacteria of Water.f — D. Fernandez has investigated the 

 bacteria of the water-supply of the town of Buenos Ayres especially in 

 relation to the pigment-bacteria. The water is derived from the Rio de 

 la Plata and is a dark yellow colour owing to the admixture of loam- 

 constituents. The bacterial contents of the water varies between 10— 

 50,000 per c.cm. before filtration through sand, which reduces the 

 number to 200-2000 per c.cm. The characters of nearly 100 different 

 forms are described, most of them being pigment-bacteria, but names 

 are given to only very few. 



Bacterium Pathogenic for House-Rats .$ — Toyama has described 

 a pathogenic bacterium fatal to the ordinary house-rat in Tokio. The 

 organism was isolated, and studied both in artificial cultures and by 

 inoculation. For mice and house-rats it was strongly virulent, but was 

 without effect on guinea-pigs and ordinary rats. It showed a number 

 of resemblances to Loeffler's B. typhi murium but did not agree in all 

 particulars ; the question as to its being a distinct species was left 

 undecided. 



Passage of Bacteria through Filters. § — Erwin von Esmarch has 

 made some important investigations on the question of the passage of 

 bacteria through filters. It has been known for some time that the 

 organisms which produce some diseases are so small as to be scarcely 

 visible if at all by the best Microscopes. The virus of peripneumonia 

 of cattle was found by Nocard and Roux to appear under the highest 

 powers merely as tiny refractive granules which passed easily through 

 the Berkefeld and Chamberland filters. The foot-and-mouth disease 

 of Loeffler and Frosch, and the disease of tobacco-leaves described by 

 Beijerinck, and several other animal affections seem to be of this class. 

 Prof. Esmarch has set himself to discover whether similarly minute 

 forms are to be found amongst the saprophytic bacteria. Various pond- 

 and ditch-waters, and a large number of infusions of decaying matter 

 were investigated by filtration through the Berkefeld filter. To the 

 filtrate were then added very various nutritive solutions to encourage the 

 growth of any bacteria that might be present. The results were, in all 

 cases but one, negative. They might, however, be explained not by the 

 absence of the minute organisms which were sought for but by the 

 want of suitable conditions of growth. 



* Centralbl. Bakt., xxxiii. (1903) pp. 135-42 (1 pi.). 

 t Op. cit., xxxii. (1902-3) pp. 34-40, 97-135. 

 J Op. cit., xxxiii. (1903) pp. 273-81. 

 § Op. cit., xxxii. (1902) pp. 561-9 (1 pi.). 



