502 SUAIMAKY OF CURKENT RESEARCHES RELATING TO 



some inert dye, such as carmine, may be stirred into the solution to 

 make the marks more conspicuous. 



Mounting Worms in Amann's Lactophenol.* — Langeron killed 

 Xematoda in 5 p.c. formalin, and then gradually substituted for the 

 fixative Amann's lactophenol (carbolic acid 20, lactic acid 20, glycerin 40, 

 distilled water 20), in which menstruum the worms were mounted. 



(6) Miscellaneous. 



Studying the Plumes of Cephalodiscus.f — W. G. Ridewood studied 

 the development of the plumes in the buds of Cephalodiscus, and 

 describes the procedure adopted. In the youngest stages the whole bud 

 was mounted in diluted glycerin, and gold size was run round the edge 

 of the cover-glass to keep it firmly in position and to prevent the 

 glycerin from accumulating dust. Most of the buds were dissected, the 

 shield being first removed by tearing through its stalk by the aid of fine 

 needles, and then the collar region, with plumes and post-oral lamella, 

 Avas removed by carefully manipulating the needles between these parts 

 and the " body " of the bud. The three parts, shield, collar-region, and 

 " body," with its stalk, were then mouuted on the same slide in dilute 

 glycerin. In some cases these three parts were drawn separately on 

 tracing paper, and the perfect bud reconstructed by a superposing of 

 these transparent sheets. No staining fiuids were used. The dissections 

 were made under a Grreenough binocular erecting Microscope, magnifying 

 20 to 40 diameters. 



Examining the Chromatin-masses of Piroplasma bigeminum.^ — 

 H. B. Fantham fixed and stained the blood-films by Romanowsky's 

 method, and in order to eliminate as far as possible sources of error 

 incidental to stained preparations, the slides were examined under 

 various kinds of illumination. These were (1) critical illumination, 

 using as the source of light the sharp edge of a paraffin flame ; (2) mono- 

 chromatic light (green or yellowish-green was best) ; (3) light from a 

 Welsbach burner or an electric lamp. Only the first two were useful ; 

 while the chromatin could always be distinguished from the cytoplasm of 

 the parasite, very bright white light failed to accurately show the relative 

 sizes of the chromatin masses, there being also a lack of detail. Too 

 strong a Hght gave wrong impressions as to size and condition of the 

 vacuoles. Daylight was also used. The objectives used were Zeiss' 

 2 and '6 mm. apochromats, with 8, 12, and 18 oculars. Relatively pale- 

 stained preparations were found to be far superior to more deeply stained 

 ones, as the finer chromatic details and the looser chromatin in the 

 latter are obscured, and the finer structural details masked. 



Appliances for Counting Blood-corpuscles, Yeast-cells, Bacteria, 

 etc.§ — C. Zeiss and Co. describe their counting chambers and mixing- 

 pipettes. The counting chamber is made by cementing a glass plate 



* C.R. Soc. Biol. Paris, Iviii. (1905) pp. -449-50. 



t Quart. Jouru. Micr. Sci., li. (1907) pp. 221-52 (11 figs.). 



: Tom. cit., pp. 297-324 (1 pi. and 44 figs.). 



§ Carl Zeiss' Special Catalogue, Jena, 1906. 



