782 SUMMARY OF CURRENT RESEARCHES RELATING TO 



bottle to prevent any dirt from interfering with the manometer. The top 

 of the thermostat is covered with a double lid which is divided into two 

 halves, each of which is surmounted by a knob for facilitating removal. 

 The object of this double lid is to keep as much heat in as possible ; one 

 half is shown separately lying on the base board of the thermostat (fig. 

 126). The temperature of the water in the jacket should range from 

 62-65° for a paraffin mixture with a melting point of about 55°. For 

 the preliminary saturation the author uses water-free aceton chloroform 

 or xylol. To start the apparatus the taps of the exsiccator and of the 

 water-pump are turned on, and after about half an hour the water-pump 

 tap is turned off. The tap of the manometer is then carefully and 

 slowly opened until the mercury in the closed limb has risen. As soon 

 as the atmospheric pressure is restored the exsiccator may be opened. 



Transparent Red Injection Mass.* — R. Krause uses a tin trough 

 28 x 15 x 10 cm. A sieve-tray rests inside, supported by the handles ; 

 the measurements are 1 to 2 cm. less than those of the trough. The lid 

 has pieces cut out to slip over the handles. The gelatin is placed in the 

 tray, and macerated in water for about 2 hours ; the sieve is then lifted out, 

 and the water allowed to drain off for j to ^ hour. It is then stained with 

 borax-carmine. 100 grm. of borax are dissolved in 2 litres of hot water, 

 and 15 grm. of powdered carmine added, after which the mixture is boiled. 

 Next day the supernatant fluid is poured off into the trough ; the tray 

 with the gelatin is then replaced in the trough. In 4K-72 hours the 

 tray is removed, the gelatin allowed to drain, and then washed several 

 times in the trough with fresh wuter. The colour is fixed by means of 

 2 p.c. hydrochloric acid, of which 5-10 litres are necessary. The gelatin 

 plates, 5 or 6 at a time, are removed from the sieve and immersed in 

 the acid until they become of a cherry red colour. After this they are 

 replaced in the tray, and the trough filled with water kept running in 

 order to remove any excess of acid (J to 1 hour). The gelatin thus 

 prepared may be preserved for future use by means of camphor. The 

 mass does not diffuse through the walls of the injected vessels ; it is 

 always transparent, and the carmine never precipitates. 



Hickling, G. — The Microscopic Study of Rocks. 



[The author deplores the fact that microscopists pay little attention to 

 the study of rocks : simple directions are given for making slides of 

 rocks.] Trans. Manchester Micr. Soc. 1908, pp. 64-70. 



(4) Staining- and Injecting-. 



Double-staining Vegetable Tissue. f— A. E. Lopez first treats the 

 sections with eau de javelle or with an • aqueous solution of chloral- 

 hydrate. After repeated washings the sections are placed in a concen- 

 trated solution of caustic potash for 10 minutes. They are again 

 washed, and then stained in a mixture of Delafield's hematoxylin and 

 1 p.c. iodine green for 10 minutes. The hematoxylin and iodine green 



* Zeitschr. wiss. Mikrosk., xxvi. (1909) pp. 1-4 (1 fig.), 

 t Bol. R. Soc. Espanola Hist. Nat., ix. (1909) pp. 237-8. 



