ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 104:9 



occupy an intermediate position between the animal and vegetable 

 kingdoms, partaking of the character of both. He believes them to 

 be of animal origin, but to have acc[uired, in certain instances, cha- 

 racters which are purely vegetable. They show no indication, as 

 some have believed, of degradation from a higher type ; their cha- 

 racters are those of evolution. They are organisms altogether devoid 

 of differentiation ; they have no nucleus, and their protoplasm pre- 

 sents everywhere a homogeneous structure. 



The author has observed in the intestines of a Nepa an organism 

 which he describes under the name Trypanosoma Berti. It is a 

 cylindrical filiform body, sometimes somewhat curved, about 18 fx 

 long, slightly swollen in the middle, and bearing at its anterior end 

 a flagellum of nearly uniform thickness. The adult individuals are 

 usually twisted in a spiral manner, and then closely resemble a 

 Sjjiyillum. He regards it as a monadiform organism in a permanent 

 spirillum-condition, and endowed with motility throughout its exist- 

 ence. Between Spirodomonas and Spirillum there is scarcely any 

 appreciable difference, the latter differing from the former only in 

 the body being more or less cylindrical. The genera Spirodomonas, 

 Trypanosoma, and Hsematomonas are included in the family Protero- 

 monadcfe, intermediate between the animal Bacteria and the Flagellata, 

 chaiacterized by their elongated or sj)iral form, the absence of nucleus, 

 and the great density of their protoplasm, 



Bacteriotdomonas can scarcely be separated from the BacteriacesB 

 except by its larger size, its continuous motion, and the presence of a 

 nucleus, and yet is unquestionably of animal nature. The nucleus is 

 but slightly differentiated, and resembles the nucleoli of ordinary 

 nuclei. The group of Bacterioidomonadege may be regarded as 

 exhibiting an approach to the nucleated Protozoa. 



On the whole the Bacteriaccae must be regarded as presenting the 

 closest affinity to the astomous Flagellata. 



Pleomorphy of Pathogenic Bacteria.* — Herr G. Hauser has 

 extended the observations on the pleomorphy of other bacteria to those 

 which are active in causing disease, especially septicsemia. He states 

 that the three species of Proteus, P. vulrjaris, inirahilis, and Zenlceri, 

 go through in the course of their life-history a wide cycle of develoj)- 

 ment, resulting in the formation of coccus-like organisms, as well as 

 bacterium-, bacillus-, leptothrix-, vibrio-, spirillum-, spirulina-, and 

 spirochajte-forms. This variation is greatly influenced by changes in 

 the constitution of the nutrient substance ; when this, for example, is 

 acid, only the coccus- and bacterium-forms are developed. The diffe- 

 rent species of the genus Proteus enter, under favourable conditions 

 of nutrition, a swarming condition, in which they display great 

 motility both on the surface and in the iuteiior of stiffened gelatin. 

 They belong, among bacteria, to the active anaerobes. All the species 

 arc pathogenous, P. vulgaris and mirahilis being especially active in 

 this way. The putrefaction caused by species of Proteus does not 



• Hiiuter, G., ' Uob.FauliiiHBhactcricn u. dercn Bezichiinf^rn zur Scpticaemie * 

 (l.") \>\i.), Leipzig, 1685. See Biol. Centralbl., v. (1885) p. 321. 



