480 SUMMARY OF CURRENT RESEARCHES RELATING TO 



of boiling water, and 125 grm. of potassium chlorate dissolved by 

 boiling in about. 250 grm. of water. These solutions are mixed to- 

 gether 5 while quite hot, then allowed to cool. Then filter, and dilute 

 the filtrate to 1 litre. This solution is applied to the wood the same 

 as a, the wood being allowed to dry thoroughly after each application, 

 (c) At the end of this operation all crystals covering the surface of the 

 wood are to be washed off with clean water, (d) Once more dry the 

 wood thoroughly and then paint over with cottonseed or raw linseed oil. 

 Leave the oil for one day and then rub dry. This preparation takes 

 about six days, allowing two days for a, two for b, one for c, and one 

 for d. The result is a beautiful black surface, which will withstand the 

 usual reagents used in biological work. 



Preparing Lantern Slides of Histological Objects.*— J. Cameron 

 employs the following method of making lantern slides, the chief ad- 

 vantage being that it saves the trouble and expense of preparing photo- 

 graphs. The first requirement is a set of glass plates, lantern size, finely 

 ground on one surface. Camera lucida tracings are made of the desired 

 specimen on the ground surface. A sheet of white paper placed behind 

 the plate makes the object more distinct. Flaws or inaccuracies in the 

 drawing are easily removed by means of a wet cloth. When the draw- 

 ing is complete the surface of the plate is covered with a layer of trans- 

 parency varnish. The film should be thin, and care should be taken 

 that the plate is quite dry before the varnish is applied. 



Instead of making a drawing directly on the plate, a tracing on 

 paper may be placed under the plate and the outlines of the object 

 copied indirectly. 



After the varnish has become quite dry it is best to place a lantern 

 slide cover-glass over the plate ; a suitable form of lantern slide mask 

 being previously inserted between the two in the usual way. 



Prints from these slides may be made, and, though negatives, are 

 useful for handing round during a communication. 



Abel, K. — Taschenbuch fur den bacteriologischen Praktikanten, enthaltend die 

 wichstigsten Detailvorschriften zur bacteriolgischen Laboratoriumsarbeit. 



7 Aufl. Wurzburg (Stuber, 1903) 108 pp., 8v>. 



Kamek, L.— Anleitung zur Durchfiihrung bacteriologischen TJntersuchungen fur 

 Klinisch-diagnostiche und hygienische Zwecke. 



Wien (Safar, 1903) 311 pp., 8vo, 118 figs., 12 plates. 



Keznik, B— Technika mikroskopicka. Briinn, 1903, 16S pp. 8vo. 



Merlin, A. A. O. E. — Amphipleura pellucida (Resolution of). 



English Mechanic, Ixxix. (1904) p. 284. 



Treadle— Amphipleura pellucida (Resolution of). Tom. cit., p. 63. 



„ „ Diatom resolving. Tom. cit, pp. 84-105. 



„ „ Pinnularia nobilis (Resolution of). Op. cit,, lxxviii. (1904) p. 554. 



M „ Ditto. Op. cit, lxxix. (1904) p. 35. 



„ „ Pinnularia nobilis (Resolution and Structure of). 



Tom. cit, p. 14 (1 fig.). 

 Villa gio— Resolution of Diatoms, etc. Tom. cit., p. 193. 



* Proc. Scot. Micr. Soc., iii. (1904) pp. 350-2. 



