ZOOLOGY AND BOTANY. MICROSCOPY, ETC. 763 



deeply staining grannies about the middle of the rod, which, uniting 

 with the outer membrane, constitute the dividing line ; the newly 

 separated ends appear thick and densely stained ; later forms show that 

 the homogeneous structure has altered to various forms of chromatin 

 network, with deep violet-stained nodes and vacuoles. Sporulation 

 commences by a condensation of the chromatin mass, and the dif- 

 ferentiation of the fertile pole ; this last is unstained, and is recognised 

 by its faint lustre, which later becomes more intense, and a network 

 structure, the nodes of which are densely violet stained chromatin 

 granules, which gradually disappear and leave an enlarged unstained 

 spore, microchemically corresponding to plastin. 



Coagulation of Condensed Milk.* — R. Greig Smith has shown that 

 the coagulation or jellifying of condensed milk is due to an infection 

 by a micrococcus. The nature of the substance that forms the jelly is 

 not a slime or gum derived from the saccharose or lactose through the 

 biochemical activity of the microbe, but is an altered condition of the 

 casein resulting from the action of an enzyme secreted by the organism. 



The micrococcus measures 1 /*, and stains by Gram's method ; on 

 agar it forms a porcelain-white raised glistening growth ; in broth it 

 forms turbidity and a coherent sediment ; there is formation of indol, 

 and nitrates are reduced to nitrites ; on potato it forms a moist, trans- 

 parent growth ; gelatin is slowly liquefied ; no gas is formed from 

 glucose. The organism resembles Micrococcus pyogenes albus Rosen- 

 bach, but it is not pathogenic to mice. 



Movement of Bacteria.f— K. Reichert, by means of a simplified 

 ultramicroscope apparatus, has demonstrated the flagella of many varie- 

 ties of bacteria in unstained condition. The best medium for these 

 demonstrations is agar condensation water, or fluid nutrient (1 p.c.) 

 gelatin. For studying the conditions that regulate the visibility of 

 flagella on dark field illumination, the author chose Spirillum voluians. 

 It was shown that neither the optical nor the osmotic relations of the 

 swimming medium have any influence, but the chemical properties of 

 the substances dissolved in the medium are of much more consequence. 



Influence of Organic Substances on the Culture of Nitrifying 

 Organisms.:}:— J. Makrinoff has shown by a number of cultural experi- 

 ments that when pure cultures of nitrifying organisms are plated on 

 solid medium composed of gypsum and magnesium carbonate, a much 

 more abundant and more energetic growth is obtained if soil rich in 

 organic matter, or dried and powdered leaves, are mixed with the 

 medium. If, however, the same organic material is added to a fluid 

 medium, the growth of the nitrifying organisms is less. 



Bacillus mycoides FluggeJ — K. Holzmuller has studied eight 

 organisms, viz. :.— B. mycoides (a), (/3), (y), and (8), B. effusus, B. olfac- 

 torius, B. nanus, and B. dendroides, all of which are nearly allied to 

 B. mycoides Flugge, differing from it and from each other in the 

 character of their spores, and in the appearances of their cultures. 



* Proc. Linn. Soc. N.S.W., xxxiv. (1909) p. 107. 



t Centralbl. Bakt., lte Abt. Orig., li. (1909) p. 14. 



% Op. cit., 2te Abt., xxiv. (1909) p. 415. § Op. cit., xxiii. (1909) p, 304. 



