ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 905 



and grey substances even more markedly than in the fresh state. 

 Moreover, if we wish to have them dry they are merely placed in 

 glycerin for a few days, and on removal the excess of glycerin is 

 allowed to drain off. 



Decalcification and Staining of Osseous Tissue.* — After alluding 

 to methods for obtaining specimens by grinding and by section of 

 bone decalcified by acids, Dr. G. Pommer advocates the advantage to 

 be derived from using bone softened by osteo-malachic or rachitic 

 changes. He states that Miillcr's fluid possesses properties hitherto 

 unnoticed by previous writers ; and that by an extensive series of 

 experiments on bones softened by disease, he has been enabled by the 

 use of certain anilin dyes to distinguish with precision between those 

 parts of bone out of which the salts have been removed artificially, 

 and those parts from which the salts are naturally wanting. 



This important property of Miiller's fluid apparently depends on 

 the fact that its acid salts decalcify less completely than pure acids. 



Decalcification by acids produces many deceptive appearances from 

 shrinkage, &c., and these are altogether obviated by the use of 

 Miiller's fluid, which while allowing the bone to be easily cut, does 

 not produce any of these deficiencies or dangers. These advantages 

 are in no way lost from long immersion or frequent change of fluid. 



The author's method of staining with anilin dyes depends on the 

 fact that those parts which have at one time contained lime salts 

 become coloured, while those which have never been impregnated 

 remain unaffected. 



The dyes, six in number, are the blue and red methyl-violets, 

 dahlia, Parma violet, safranin, and methyl-green. The strength of 

 the solution is for the violets • 02 per 1000 ; for dahlia • 04 per cent. ; 

 for safranin "1 and '16 per cent.; and for methyl-green '3 per 

 cent. The sections are allowed to remain in solution from 12 to 

 18 hours. The first five give a dark stain, the last only a j)ale green. 



Staining the Nucleus of the Germinal Vesicle in Arthropoda.f — 

 Though the methyl-green and acetic acid solution recommended by 

 Mayzel and Strasburger usually produces a good nuclear stain, Dr. 

 V. Wielowiefski states that the nucleus of the germinal vesicle in 

 Arthropoda, and as he suspects in all animals, is absolutely, or 

 almost, unstainable even though the cell bo completely isolated in 

 order that the staining fluid may have certain access to the nucleus. 

 Only a few cell nuclei, e. g. the nuclei of nerve-cells and of Gre- 

 garinae, show this peculiarity. 



Double Injections for Dissecting Purposes. J— Professor H. F. 

 Ofibom's method for double injections § was to fill the wlicde vascular 

 system with a thin coloured injection-mass. Wlien this has passed 

 through the capillaries and well filled the veins, there is forced into 

 the artery a ditferently coloured plaster mass which pushes the 



♦ Z< itschr. f. Wifls. Mikr., ii. (188.5) pp. 151-C. 

 t Biol. Ccntralbl., iv. (1881) [.p. .360-70. 

 X Amer. Natural., xix. (188.5) pp. .026-7. 

 § Scf; lliiM .Joiirnal, iv. (1881; p. :{2.i. 



