ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 115 



temperature. A further advantage of the apparatus is that it can be 

 used with gas or with a paraffin lamp as desired. In the illustration 

 (fig. 30) a paraffin lamp is seen in position. A damper, which risen 

 with the increasing temperature, controls the heating effect of the lamp. 

 The device by means of which the damper is actuated depends on the 

 relative expansion of two metals, aluminium and nickel steel ; their 

 disposition being such that the hotter the bath becomes the higher the 

 damper is raised, so that the heat supplied to the bath becomes corre- 

 spondingly less. Very close regulation of temperature is claimed for 

 this apparatus, a constancy within 1° C. being readily maintained with- 

 out the attention of the operator being required. The temperature to be 

 maintained can be readily adjusted to a higher or lower point on the 

 scale by a simple setting of the regulator. The bath is provided with 

 an equipment of wax-pans, bottles, and so forth. 



(4) Staining: and Injecting-. 



New Method of Making Romanowski's Chromatin Stain.* — 

 Giemsa uses the following receipt: Azur ii. eosin, 3*0 grm. ; and 

 Azur ii., 0*8 grm., are placed in a desiccator over sulphuric acid and 

 well dried, thoroughly pulverised, sifted througji a fine-meshed silk 

 sieve, and dissolved by shaking up with glycerin, 250 grm. (Merck 

 chem. rein), at 60° C. Methyl-alcohol, 250 grm. (Kahlbaum 1), pre- 

 viously warmed to 60° C, is then added to the mixture and well shaken, 

 allowed to stand for 24 hours at room temperature and then filtered, 

 and the solution is ready for use. He gives the following directions 

 for using the stain : (a) the film dried in air is fixed in ethyl-alcohol, 

 or for 2-3 minutes in methyl-alcohol, and dried with blotting-paper ; 



(b) dilute the staining solution by shaking up 1 drop in about 1 c.cm. 

 of distilled water (warming the water to 30°-40° C, assists the stain) ; 



(c) cover the film preparation with the freshly diluted solution, and 

 stain for 10-15 minutes ; (d) wash in running water ; (e) dry with 

 blotting-paper and mount in Canada balsam. 



Staining and Preserving Algae. — J. Q. T. gives the following 

 particulars of a method of staining and preserving algas, which he has 

 found very satisfactory. The reagents required are made up as follows r 

 Fixing solution : chromic acid, 1 oz. ; glacial acetic acid, 4 oz. ; for- 

 maldehyde as formalin (Schering's), 4 oz. Preserving fluids : best 

 glycerin, 8 oz. ; glycerin jelly, 1 oz. Chromo-acetic acid : chromic 

 acid, 1 grm. ; acetic acid, 1 c.cm. ; water, 100 c.cm. Formalin (4 p.c.) : 

 Schering's formalin, 10 c.cm. ; water, DO c.cm. (for a 2 p.c. solution 

 take half the quantity of formalin). Stains : hasnialum (Griibler) ; 

 hgeniatoxylin solution : hematoxylin cryst. puriss., 1 grm. ; water, 

 200 c.cm. Iron alum solution : iron alum, 3 grm. ; water, 100 c.cm. 

 (The iron alum should be in pale violet crystals, not yellow or green, 

 and should be kept in an air-tight tube.) Eosin solution (water 

 soluble) : eosin, 1 grm. ; water, 200 c.cm. 



* Centralhl, Bakt.. 1'" Abt. Orig., xxxvii. (1904) pp. 308-11. 

 t Knowledge, i. (1904) pp. 305-0. 



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