490 RECOBD OF CURRENT RESEARCHES RELATING TO 



should become infected with only one variety, and that the germs of 

 the other variety, which would be jtist as likely to be present in air to 

 the same extent, should have no influence. 



Effects of Temperature on Bacillus anthracis.* — Professor Frisch 

 has experimented on the effects of abnormally low temperatures on 

 these organisms. The instrument of investigation brought the tem- 

 perature down to — 111°, where it remained for half an hour, and then 

 gi-adually rose ; on the whole the test-fluids may be said to have 

 been for about five and a half hours at — 22 • 5° C. Notwithstanding 

 this enormous change in their condition the Bacilli were apparently 

 uninjured, for the growth of filaments and the formation of spores 

 went on as before ; when, however, they were used for injection 

 purposes, the experiments were found to be in one sense successful, 

 for there were no rods found in the blood of the animals injected, 

 and the spores only once developed their characteristic figure ; the 

 latter result shows that against extreme cold, just as against all other 

 adverse circumstances, the spores have a greater power of resistance 

 than the homogeneous rods. 



Unfortunately the Bacteria of diphtheritis and jiuerperal fever did 

 not experience any harm from being cooled down to — 87 • 5° C. 



Fungus-pests of the Potato. t — The exhaustive work by Eeinke 

 and Berthold on this subject is divided into three sections. The 

 first treats of the moist decay of the potato tubers, the authors regard- 

 ing as the direct cause of this disease the appearance in the plant of 

 bacteria, Bacillus subtilis Cohn, and a new form, called by the authors 

 Bacterium Navicnla. Potatoes weakened by the PhytojphtJwra are 

 especially, though not exclusively, predisposed to this form of disease. 

 Other Schizomycetes may also co-operate. The decay is then further 

 promoted' by other saprophytic fungi. 



The second section of the book treats of the history of development 

 of the most important of these : — Hypomyces Solani, a pyrenomycete 

 whose conidial form is known as Fusisporium Solani; Nectria 

 Solani, the conidial form of which is known as Spicaria ; Chcetomium 

 hostrychofles and crispatum, Stysanus Stemonitis and capitatus, and 

 Verticillium (Acrostalagmus Cord.) cinnaharinum. The third section 

 is concerned with the crinkling of the leaves of the potato, the cause 

 of which disease is referred by the authors to the attacks of a fungus 

 which they name Verticillium alboatrum. 



Spirochsete denticola.J — The organism which is always found 

 in the mucilage of the teeth and tongue, and often in close connection 

 with the epithelium, has been made a subject of investigation by 

 Dr. Rudolf Arndt. In connection with the epithelium are true 

 Bacteria, Bacilli and Vibriones. Among the zoo^Zcea-colouies are also 

 traces of colonies of Bacillus and Leptothrix ; and together with 

 these the peculiar Spirochcete denticola, consisting of spirally coiled 



* 'Zeitschr. gesammt. Naturwiss.' (Giebel), Hi. (1879) p. 884. 

 t ' Die ZersetzuDg der Kartoffel durch Pilze,' von J. Eeinke u, G. Berthold. 

 9 Taf. Berlin, 1879. See ' Bot. Zeit.,' xxxviii. (1880) p. 44. 

 X ' Arch. path. Anat. ix. Phys.' (Virchow), Ixxix. (1880) p. 76. 



