250 SUMMARY OF CURRENT RESEARCHES RELATING TO 



For staining purposes, alcoholic solutions of pigments or the dry 

 pigments may be dissolved in aceton. 



For mounting purposes, solutions of mastix, balsam, styrax, may be 

 dissolved in aceton, and make serviceable preparations. Celluloid solu- 

 tion dissolved in aceton, and rubbed up with cinnabar, chromoxide, 

 ultramarine, or zinc white, makes an excellent lac or cement for ring- 

 ing round preparations, etc. This celluloid cement may be used for 

 multifarious purposes in the laboratory, e.g. for stopping gas-leaks, 

 sealing corks, mending broken apparatus, and so on. 



The addition of a little amylacetate imparts a greater elasticity to 

 the cement. If gum-soaked preparations be exposed to the action of 

 aceton vapour before cutting, they are more easily sectioned. Aceton, 

 like alcohol, ether, and l)enzin, is inflammable. 



t6) Miscellaneous. 



Barberio's Spermatic Reaction.* — J. B. Levinson calls attention to 

 this reaction, whicli is described as follows. Spermatic fluid or a con- 

 centrated solution of it is added to saturated solution, aqueous or 

 alcoholic, of picric acid. Needle-shaped rhombic crystals of a yellow 

 colour, like Charcot crystals in shape, are formed. 



Metallography, etc. 



Copper Steels.f — P. Breuil states that in steels containing carbon 

 O'oG-O'Tl) p.c, copper 0*o-2() p.c, the point Ar 1 occurs between 575' 

 and 600° C. In alloys with 8 p.c. or more copper, a separation of 

 copper or of an iron-copper alloy occurs, and a critical point is found at 

 about 10(»(r C. A number of tensile test results given by the author 

 show that copper increases the tenacity and lowers the ductility of the 

 steel, the extent of this effect varying with the treatment to which the 

 steel is subjected. 



A Method of Measuring the Resistance of Metals to Rapid 

 Deformation.! — P. \'ieille and R. Liouville, l)y simultaneously com- 

 pressing two identical copper crushers, separated by a light steel piston, 

 by ballistic pressure developed by an explosive, have shown that the 

 inertia forces are negligible. The displacements of the piston receiving 

 the pressure of the gases, and of the piston separating the two crushers, 

 are recorded on a revolving drum. The ordinates of the first curve are 

 double those of the second. If now the second crusher has been 

 previously submitted to a given static pressure, it commences to deform 

 when that pressure is reached. This point is sharply indicated as the 

 origin of the time-compression curve of the previously compressed 

 cylinder. From the two curves, the compression of the new crusher, 

 the velocity of compression, and the actual pressure at this point are 

 obtained. The authors show that the amount of compression for a given 



* Berlin Klin. Wochenschr, Oct. 8, 1906. See also Brit. Med. Jouru., 1907, i. 

 Epit. 32. t Coinptes Rendus, cxliii. (1906) pp. 346-8. 



X Tom. cit., pp. 1218-1221. See also this Journal, 1906, p. 514. 



