ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 1097 



ethylato. This body can also bo prepared synthetically by treating 

 a solution of cinnamic acid in ethylic alcohol with hydrochloric 

 acid gas. After standing for months this fluid, at first as clear as 

 water, begins to grow cloudy from the presence of amorphous 

 particles, which by their increase, render the fluid quite thick in the 

 course of years. This appearance is due to polymerism, a condition 

 to which all the derivatives of cinnamic acid are liable. Conse- 

 quently, after long standing, the quantity of the solid constituents of 

 storax increases at the expense of the fluid. 



Carbolated Glycerin-gelatin.* — Seflor Lazaro e Ibiza, who has 

 been experimenting with carbolated glycerin-gelatin as a substitute 

 for Canada balsam, remarks that gelatin being much more soluble hot 

 than cold, it is possible to obtain solutions which, saturated at 50°, 

 60°, 70 3 , or higher, are solid at the ordinary temperature of museums 

 and laboratories. A piece of this gelatin, slightly warmed on a slide, 

 melts and allows the object to become immersed in it, and after 

 putting on a cover-glass, the gelatin solution solidifies, thus keeping 

 the object in position and firmly fixing the two glasses. 



The xise of this substance offers two advantages. (\) The point 

 of concentration of the substance is obtained on preparing the solution. 

 (2) Cleaning tho preparation is effected by merely washing the edges 

 with a brush and water. The author uses Kaiser's formula : f gelatin 

 1 part ; water 6 parts ; glycerin 7 parts. The gelatin is macerated 

 in water for two hours; the glycerin is then added and also pure 

 carbolic acid, in the proj^ortion of 0*01 of the mixture. It is then 

 boiled for ten minutes and filtered while warm. 



Ajiart from its general advantages, carbolated glycerin-gelatin 

 may be recommended for those substances which are dry or but little 

 juicy. The author has found it excellent for the preservation of 

 diatoms, pollen, epidermis, and wood-sections. Moreover, it offers 

 great facilities when preparations are only required for a few days 

 or months, as the slides are easily cleaned by merely washing in 

 water. If the preparation is to be kept indefinitely the edge of the 

 cover-glass should be cemented down, for if not, the gelatin becomes 

 slightly coloured, probably from tho volatilization of the antiseptic, 

 and hence the author suggests the substitution of salicylic acid. It 

 is not advisable to use this gelatin mixture for mounting soft objects, 

 the juices of which are easily alterable. 



The possibility of obtaining preservative media which are liquefi- 

 able at very low temperatures (30*5°) affords the opportunity of 

 preserving algoe and delicate fungi which are unable to resist tho 

 disorganizing action required for mounting objects in balsam. 



Mounting in Glycerin-jelly 4 — Mr. W. T. Suffolk, a member of 

 the committee appointed to examine the cabinet of the Society, found 

 that whilst in all cases slides properly mounted in balsam were 

 unaltered, the objects mounted in glycerin-jelly had been affected by 



* Anal. Soc. Espaiiola Hist. Nat, xiv. (1885), Actas, pp. 12-5. 



f See this Journal, iii. (1880) p. 502. 



X 15lh Ann. Rep. South London Micr. and Nat. Hist. Club, 1886, p. 13. 



