<S8 SUMMARY OF CURRENT RESEARCHES RELATING TO 



Presence of Bacteria in Echinococci and Cysticerci.* — R. Mehl- 

 hose, in an important communication, draws attention to the bacterial 

 contents of the bladder-forms of tapeworms. The author presents his 

 case in tabular form, and cites sixty examples, and afterwards describes 

 the bacteria. 



Flagella of Spirillum volutans.t — F. Fuhrman found that these 

 varied in number from fifteen to twenty-five. They rise for the most 

 part in a single tuft at a point near one pole, but smaller secondary 

 tufts occur. The average length is 12-18/*, but in older cultures 

 flagella of much greater length, as much as 72 /a, are seen. Their thick- 

 ness is estimated at * 03-0 ' 05 /a. Flagella are described as consisting 

 of a proximal portion, starting from a point in the cell-plasma situated 

 near the pole, and passing to the cell-membrane, and of a distal free 

 portion, beginning at the outer aspect of the cell-membrane. The free 

 portion is normally structureless. The proximal portion is a fine thread, 

 resembling somewhat a chromatin-fibre. The point of origin is analo- 

 gous to the blepharoplast of Flagellates. 



Causes of certain Plant Diseases.:}: — A. Osterwalder describes a new 

 species of bacterium, Pseudomonas levistici, parasitic upon Levisticum 

 officinale, which makes stains upon the leaves and dark brown streaks 

 upon the stem. It is a small organism, rounded at one end and pro- 

 vided with a terminal flagellum. It grows well on nutrient agar and 

 on gelatin, which it liquefies. It forms indol. and is Gram-negative. 

 Spore-formation has not been observed. 



Phytophthora omnivora is parasitic upon Calceolaria rugosa. The 

 disease spreads from the stem, causing the plant to wither and die. 



Sclerotinia libertiana causes a fatal disease in Omphalodes verna. 



Che/one glabra and G. barbafa are attacked by Tylencephalus de- 

 vastatrix, a Nematode, which, in the former species, causes remarkable 

 distortions of the stem. 



Comparative Studies of the Myxobacteriaceas and the Bacteri- 

 aceae.§ — C. Vahle gives an account of his work upon some of the 

 Myxobacteria. The types investigated were the Myxococcus ruber. 

 Myxococcus virescens, Polyangium fuscum, and Chondromyces crocatus. 

 The author gives an exhaustive account of the development and mor- 

 phology of the spores and the vegetative forms. These organisms djffer 

 in some important respects from the bacteria proper. In Myxobacteria 

 fission takes place by the drawing apart of the daughter-cells rather 

 than by the formation of a septum, as in bacteria. The true cell- 

 membrane of bacteria is represented in Myxobacteria by an adhesive 

 pellicle of a different nature. Myxobacteria possess no flagella, and 

 their mechanism for movement has not been clearly demonstrated. The 

 development, morphology, and germination of the spores show further 

 points of difference. On the other hand, a comparison of these types of 

 Myxobacteria with certain of the Myxomycetes shows many striking- 

 points of similarity, more particularly in respect of methods of repro- 



* Centralbl. Bakt., lte Abt. Orig., lii. (1909) pp. 43-74 (1 pi.). 



t Op. cit., 2te Abt., xxv. (1909) pp. 135-59. J Tom. cit , pp. 260-70. 



§ Tom. cit., pp. 178-260. 



