GGO SUMMARY OF CURRENT RESEARCHES RELATING TO 



growths, although comparatively infrequent, have in several cases been 

 studied, and the presence of an unpleasant odour in the water has been 

 proved to be associated with their presence. Some description of the 

 forms observed is given. 



Trichocysts of Paramecium.* — P. Mitrophanow interprets the 

 trichocysts as an excretory apparatus. By contraction of the ectoplasm 

 they squirt out their contents, and this hardens in the water into a 

 thread. The material for the trichocysts is formed as granular or 

 irregular bodies in the endoplasm, in the neighbourhood of the nucleus 

 and with its assistance. 



Nucleus of Paramcecium.f — P. Mitrophanow has made sections of 

 Paramoecium, and has discovered details regarding the structure of the 

 macronucleus. There are rows of chromatin granules arranged trans- 

 versely with achromatin between. What look like chromatin rods are 

 tubular folds packed with chromatin granules. His scholars, P. A. 

 Chainsky and B. Petschenks, also contributed to this intricate study. 



Stalk of Vorticella.l — E. Faure has made a study of the intimate 

 structure of the stalk of Vorticella convallaria, which consists of an 

 internal contractile axis, and an external elastic sheath. The contractile 

 central cord includes (a) the essentially active part, composed of united 

 myonemes, the tubular " spasmonema" disposed in a long spiral ; (b) a 

 plasmic cord formed of minute granules, doubtless united by a hyalo- 

 plasmic network, and describing a spiral parallel to that of the spas- 

 monema, and (c) an enveloping sheath. A physiological interpretation 

 of the contraction is attempted, but it all seems highly problematical. 



Note on Klossiella muris, g. et sp. n.§— H. M. Woodcock re- 

 interprets some of the observations of Smith and Johnson on this 

 parasite. They described as the sporogonic cycle a stage characterised 

 by the development of twelve to fourteen spherical spores, each con- 

 taining thirty to thirty-four banana-shaped sporozoites. According to 

 the author, their figures leave no doubt that the stage which they have 

 described as sporogonic is nothing more nor less than merogony or 

 schizogony, while the other part of the cycle regarding which they give 

 no decided opinion, is in all probability the commencement of gametocyte 

 formation. 



Trypanosome of Rabbit.|| — G. F. Petrie records the occurrence of 

 a trypanosome in the blood of rabbits. It does not appear to be of 

 frequent occurrence, and artificial infection is not easily produced, 

 although experiments seem to indicate that trypanosoma blood is toxic 

 to certain uninfected rabbits. The parasite is not essentially different 

 from that of the rat trypanosome, although it is smaller. 



* Arbeit. Zool. Lab. Univ. Warschau, xxxii. (1903) pp. 1-18 (0 figs.), Russian. 

 See Zool. Centralbl., xi. (1904) pp. 510-11. 



t Op. cit, xxxi. (1903) pp. 1-48 (31 figs.) Russian. See Zool. Centralbl. xi. 

 (1904) pp. 503-10. 



t Comptes Rendus, cxxxviii. (1904) pp. 994-6. 



§ Quart. Jour. Micr. Soc, xlviii. (1904) pp. 153-63. 



| Centralbl. Bakt. Parasitenk., xxv. (1904) pp. 484-6. 



