ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 377 



any medium which, contained glucose or cane sugar, and abundance of 

 gas was produced in cane sugar gelatin shake cultures. 



Experiments with sound tins of milk were made for the purpose of 

 proving that the blowing was due to the vital activity of the small torula. 

 The results were positive. 



Investigation of the cane sugar used in the manufacture of a batch 

 of blown tins, proved the absence of the torula, though a gas-forming 

 bacterium was isolated from some cultures. But though this organism 

 had the power of forming gas, it was shown that this activity was 

 inhibited by increase of sugar in the medium. 



(2) Preparing- Objects. 



Demonstrating Life-Cycle of Cystobia irregularis.* — H. M. Wood- 

 cock, when examining Holothuria and Gucumaria for " Cystobia " irregu- 

 laris (Minch), stupefied the hosts by placing them in sea-water, to which 

 a few crystals of menthol had been added. In Holothuria the parasites 

 are seen as white oval spots in the lumen of vessels, or as spherical cysts 

 attached to the wall. In Cucumaria the parasites are found in the 

 respiratory trees, or attached by a stalk to the cajloniic epithelium. The 

 latter are adults, and enveloped by a double layer of epithelium. 



The adults were usually fixed on the slide with osmic acid vapour 

 (5 min.). After washing with water, the preparations were stained with 

 dilute picrocarmin (Ranvier), and afterwards mounted in balsam. 



Another method was to fix in saturated aqueous sublimate, to which 

 5 p.c. glacial acetic acid had been added. Such preparations were stained 

 with carm-alum, or with alcoholic paracarmin. 



For gregarines and for cysts, the sublimate acetic solution (20-40 

 minutes), or Flemming's fluid (2-4 hours), gave the best results. By 

 the former method the material was stained in bulk with borax or para- 

 carmin, by the latter on the slide. Sections of cysts were stained with 

 iron-hgematoxylin, followed by orange or eosin, with thionin and orange, 

 with Kleinenberg's hematoxylin, and with other solutions, but tbose 

 mentioned gave the best results. 



Fixation Method for demonstrating Bacterial Capsules.f — H. 



Kayser exposes the films to the action of the vapour arising from 5 c.cm. 

 1 p.c. osmic acid, to which have been added 10 drops of acetic acid for 

 about 2 or '6 minutes. After drying in the air, the film is washed for 

 1 minute with a dilute aqueous solution of permanganate of potash (a 

 small crystal to 50 c.cm. water), and then washed in water. 



Staining of the capsule may be done by the method of Klett, Johne, 

 Heims, or others. 



Demonstrating the Structure of Cladosphora Membrane.! — F. 

 Brand treated the material for at least 24 hours with acidulated dis- 



* Quart. Journ. Micr. Sci., 1. (1906) pp. 1-100 (6 pis.). 

 t Centralbl. Bakt., 1 ( « Abt., Orig., xli. (1906) pp. 138-40. 

 1 Ber. Deutsch. Bot. Ges., xxiv. (1906) pp. 64-70 (1 pi.). 



