508 SUMMARY OF CURRENT RESEARCHES RELATING TO 



development. The author roughens one surface of the slips by means 

 of hydrofluoric acid. In a lead capsule, the lid of which is perforated 

 by several holes, the diameter of which is equal to two-thirds of that 

 of the slips, is placed a mixture of calcium fluoride and sulphuric acid. 

 The hydrofluoric acid vapour corrodes the glass surface, and as soon as 

 one slip becomes whitish it is replaced by another. 



The fine and regular roughness thus produced interferes with 

 observation much less than may be supposed, provided the illumination 

 be suitable, and certainly allows the progress of growth to be watched 

 satisfactorily. 



Collecting and Preserving Planocera inquilina.* — F. M. Surface 

 obtained the material from the branchial chambers of the large whelk, 

 Sycotypus canaliculatm, during July and August at Woods Hole. About 

 three or four worms were obtained for every whelk opened. The adult 

 polyclads were transferred to dishes of sea-water, in which the water was 

 changed by means of a system of balanced siphons. These siphons 

 served to keep the water free from sand and dirt, and also prevented 

 the overflow of the water and the escape of the worms. 



The animals soon laid eggs in spiral, gelatinous capsules, containing 

 from 100 to 2000 eggs apiece. The tough capsules are very difficult to 

 penetrate with fixing and staining reagents. 



Stages from the maturation of the ova to the free-swimming larvae 

 were obtained without difficulty under laboratory conditions. The adult 

 animals, however, only lived for a few days. 



Eggs were fixed in various solutions : sublimate-acetic, 95 p.c. 

 alcohol, Gilson's mercuro-nitric, picro-sulphuric, picro-acetic, Perenyi's 

 and Flemming's solutions. Of these Gilson's fluid and the sublimate- 

 acetic were found to be the best. For staining whole mounts Conklin's 

 picro-hgematoxylin was used ; but stronger solutions were found better 

 for these eggs. The eggs were then clarified in xylol and mounted 

 in balsam. 



Owing to their small size it was impossible to remove the eggs from 

 their capsule, but they cleared better if the capsule was torn. It was 

 found necessary to bleach the Flemming material with peroxide of 

 hydrogen before sectioning. A number of stains were used for the 

 sections, but Delafield's hematoxylin, either in toto or on the slide, 

 proved most useful. A combination of thionin and acid-fuchsin also 

 gave good results. There is too much yolk in these eggs to use 

 Heidenhain's iron-alum hematoxylin to advantage. 



Cultivating the Parasites of Kala-azar and lAleppo Boil.f — 

 C. Nicolle has cultivated successfully the parasites of Aleppo boil and of 

 Kala-azar on the following medium : — agar 14 grm., sea-salt G grm., 

 water 1)00 grm. This is distributed in test-tubes and sterilised ; next 

 the tubes are liquefied at 55°, and one third of rabbit's blood obtained 

 aseptically from the heart is added. The tubes are sloped for 12 hours 

 and afterwards incubated at :-57° for 5 days. They are preserved for 

 future use at room temperature. The inoculations were made in the 



* Proc. Acad. Nat. Sci. Philadelphia, lix., 1907, pp. 514-59 (6 pis.), 

 t Comptes Rendus, cxlvi. (1908) pp. 498-9, 842-3. 



