ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 93 



fungi, but that it is a very pleomorphic streptothrix, which, in addition 

 to changes of form, exhibits marked changes in its staining reactions 

 ■with regard to acid-fastness. The author has obtained in culture the 

 following phases of the organism : — (1) A non-acid fast streptothrix 

 in the mycelial stage, and prol acing acid-fast rods ; (2) a non-acid fast 

 diphtheroid bacillus, producing also acid-fast rods : this is really a strepto- 

 thrix ; (3) an acid-fast bacillus, which is but the broken-down stage of 

 a streptothrix ; and (4) an acid-fast mycelium. The author also makes 

 some observations upon the application of vaccines to the treatment of 

 this disease. 



New Type of Diplococcus.* — L. S. Dudgeon and P. N. Panton de- 

 scribe a type of diplococcus isolated from the urinary tract, which in 

 its staining properties, morphological appearances, and in the nature of 

 its growth upon agar, closely resembles the pneumococcus. It ferments 

 dextrose, mannite, maltose, lactose, saccharose, and salicin, and grows 

 well in His's serum inulin, without producing any alteration in the 

 medium. Litmus milk is turned acid and rapidly decolorized. This is 

 the most characteristic cultural feature. It has little or no pathogenic 

 effect upon rats and mice, and may be found in man, unaccompanied by 

 any evidence of disease. Probably this organism has on several occasions 

 been identified, erroneously, with the pneumococcus. 



Influence of Ionized Air on Bacteria. f — W. P. Thornton exposed 

 cultivations of bacteria to the electric wind from charged needle-points, 

 and found that after subsequent incubation the wind from negatively 

 charged points had more bactericidal effect than from points positively 

 charged. After excluding various influences — such as that of ultra- 

 violet light — to which the bactericidal effect might be ascribed, it is 

 inferred that the whole effect may be attributed to the direct influence 

 of and contact with ions in the electric wind. 



In connexion with these and previous experiments it is suggested 

 that chemiotaxis may be explained by the attraction of the positively 

 charged bacteria to the large negatively charged leucocytes. When fresh 

 blood is used the electrical charges are very fixed and characteristic, 

 while the charge of bacteria reverses when the culture is kept for several 

 days. The negative chemiotaxis of Bordet would then have to be in- 

 terpreted by some such reversal occurring in the infected animal on 

 account of changes in the blood-serum or peritoneal fluid. 



Bacteriology of the Cockroach. | — C. C. Morrell, in an interesting 

 paper, records his experiments on ihe faeces of the cockroach. He finds 

 that the common cockroach is able by contamination with its faeces (1) to 

 bring about the souring of milk ; (2) to infect food and milk with 

 intestinal bacteria ; (3) to transmit the tubercle bacillus ; (4) to dis- 

 seminate pathogenic cocci ; (5) to transmit from place to place destruc- 

 tive moulds. The author's view as to the future of these insects and 

 their pathogenic action is highly pessimistic. 



* Lancet, (1911) ii. p. 1696. 



t Proc. Roy. Soc, Series B, Ixxxiv. (1911) pp. 280-8 (6 pis.). 



X Brit. Med. Journ. (1911) ii. pp. 1531-2. 



