ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 523 
Pyocyanin and its Mutations.*— According to Herr G. W. Boland, 
B. pyocyaneus forms only two pigments. One of these, formed also by 
many other bacteria, fluoresces. The second pigment, pyocyanin, owing 
to some oxidising action which takes place outside the medium, is con- 
verted into pyoxanthose ; while, owing to certain at present uuknown 
changes occurring within the medium, it passes into the red-brown 
pigment so frequently seen in old cultures. 
Production of Amyloid Degeneration.!— Dr. E. Schepilewsky has 
produced amyloid degeneration in animals by injecting them with living 
bouillon and cartilage emulsion cultures of Staph, pyogenes aureus , by 
the injection of devitalised cultures of Staph . pyogenes aureus , and by the 
injection of ferments, e. g. rennet, pancreatin, and papayotin. The 
amyloid degeneration is, therefore, producible without the co-operation 
of living organisms or of bacterial products. It is most easily and 
certainly set up by injecting rabbits with large quantities of cultures 
of Staph, py. aureus , devitalised or attenuated by means of chloroform. 
The amyloid substance is also found in rabbits which have suffered from 
prolonged suppuration unconnected with bacteria. The appearance of 
true amyloid in the spleen, demonstrated by the characteristic reaction 
to anilin dyes, is preceded by a hyaline stage, which histologically closely 
resembles amyloid, but is distinguished therefrom by its reaction to the 
anilin pigments. 
Reducing Action of Denitrifying Bacteria.! — Sig. G. Ampola and 
Sig. C. Ulpiani point out that denitrifying bacteria do not attack 
asparagin or nitro-methane, and their action on ethvlic nitrate is very 
slow. From this it is inferred that denitrification takes place only with 
oxygen compounds of nitrogen, and only with such of these as are 
electrolytes and are thus dissociated into ions in solution. Denitrifying 
bacteria are arranged under three heads: — (1) Those which destroy 
nitrites but not nitrates, e. g. Bacterium denitrijicans ; (2) those which 
destroy nitrates but not nitrites, e. g. Bacillus pyocyaneus and Bac- 
terium denitrijicans v. ; (3) all other denitrifying bacteria which attack 
both nitrites and nitrates. 
Examination of the action of B. denitrijicans on metallic nitrates 
showed that the more electro-positive the metal, and the lower its 
atomic weight, the more rapidly does denitrification take place. The 
nitrates of certain alkaloids, brucine, strychnine, cocaine, pilocarpine, 
which are entirely ionised in solution, are soon denitrified. 
Decomposition of Cement by Bacteria.§ — According to Herren A. 
Stutzer and R. Hartleb, the loss of calcium by cement exposed to the 
prolonged action of potable water is not only due to the solvent property 
of carbonic acid, but also may depend to some extent on the action of 
bacteria. The brownish muddy residue of a cement which had lain 
long in water was washed with sterilised water, and then added to a 
solution of ammonium sulphate (1 grm. per litre). In six days nitrite 
was found to be present, and in fourteen days the ammonia had entirely 
* Centralbl. Bakt. u. Par., l te Abt., xxv. (1899) pp. 897 902. 
f Tom. cit., pp. 849-62. 
i Gazaetta, 1899, 29, i. pp. 49-72. See Journ. Chem. Soc., 1899, Abstr. ii. p. 444. 
§ Zeit. angew. Chem., 1899, pp. 402-3. See Journ. Chem. Soc., 1899, Abstr. ii*. 
p. 505. 
