ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 593 



tained from strains of nearly allied organisms belonging to the Pro- 

 dig iosus group, obtained from various sources. The author finds that 

 there is a high degree of interaction between those members of the 

 group that are classed together by their sugar-fermenting properties ; 

 that there is agglutinative interaction among the members of the 

 group that tend to lose the power of pigment-formation, including 

 one strain that produces only a soluble red pigment ; there is much 

 confusion and inequality of interaction among other members of the 

 group that are closely related biologically. The difference between 

 agglutinogens power and agglutinability is due in some cases to a viscid 

 capsular condition of the bacilli. Readily agglutinable cultures do not 

 possess correspondingly high agglutinogenic power. Experiments to 

 determine the optimum temperature for the agglutination process showed 

 that better results were obtained at either 0° C. or 55° C. than at room 

 temperature or at 87° C. 



Plasmoptysis of Bacteria.* — A. Meyer has repeated his own obser- 

 vations and those of A. Fischer, and is of opinion that plasmoptysis as 

 described by Fischer does not occur. Operating with B. cylindricus in 

 small hanging drops of water, to which most minute portions of agar 

 from agar cultures of various ages have been added, the author finds 

 that sooner or later there is an active division of the rods which become 

 changed to cocci — which again later (50 hours) become shrivelled and 

 destroyed. 



Bacterial Disease of Sesamum orientale.f — K. Malkoff finds that 

 this disease attacks the stalk and leaves of the Sesamum plant, causing 

 a black decay. It is produced by bacteria belonging to two distinct 

 species : one forming yellow, the other grey colonies on nutrient gelatin, 

 the latter liquefying the medium within three days, the former causing 

 very slow liquefaction or none at all. Both varieties grow well on sugar 

 agar, and on potato ; neither organism coagulates milk, but after eight 

 days the grey colonies peptonise the milk ; the bacilli of the yellow 

 colonies are small slightly motile rods covered with long flagella ; the 

 bacilli of the grey colonies are longer, and possess a snake-like move- 

 ment, the flagella being situated only at one end. On examining 

 various portions of the plants at different stages of the disease, it was 

 found that on those more recently attacked the yellow variety pre- 

 dominated, whereas the other variety was more often met with in the 

 later stages of the disease, and especially on the older and thicker stems. 

 The author suggests that these two organisms have a symbiotic 

 existence. 



Cytology of Bacillus maximus buccalis.J — N.H.Swellengrebel, from 

 a detailed study of the cytology of this organism — comprising, besides 

 observation on the chemical and staining reactions, a careful examina- 

 tion of the peculiar cell-division — is of opinion that the spiral filaments 

 seen in the body of the bacillus should be regarded as homologous with 

 the nuclei of higher plants and animals. The author discusses fully the 

 work and opinions of other writers on the subject. 



* Ber. Deutsch. Bot. Gesell., xxiv. (1906) p. 208. 



t Centralbl. Bakt., 2te Abt., xvi. (1906) p. 664. J Tom. cit., p. 617. 



