612 RECORD OF CURRENT RESEARCHES RELATING TO 



The memoir is illustrate! by three plates, which show the very 

 striking effects iiroduced by the corrosion process : two of his figures 

 are reproduced on Plate XVIII. 



Plate XVIII. Fig. 1. — Kidney of rabbit. Injected from renal 



artery with olive oil, frozen, treated with osmic acid and 



aqua Javelli ( X 100). The large veins are seen accompanied 



by the finer arteries, ou the branches of which are the glomeruli ; 



one of these is filled with the blackened fat ; the vasa efferentia 



are seen to j^ass into the capillaries. 

 Fig. 2. — Vessels of iris of tortoise. Injected from aorta with 



olive oil, and treated with osmic acid and aqua Javelli (x 10). 



The circlet of vessels is complete, but separated in j)reparation. 



From a photograph. 



Staining-fluids * — Prof. H. Grenadier publishes a notice of some 

 new methods of staining, which he considers superior to those already 

 known, especially as applied to nuclei. 



1. Alum- carmine. —A 1 to 5 per cent, solution of common or ammo- 

 nia alum in water is boiled for 10 to 20 minutes with ^ to 1 per cent, of 

 powdered carmine, and the solution filtei*ed when cold. The solution 

 is of a rich red colour, inclining to jmrple, and, when concentrated, 

 stains a section in 5 to 10 minutes. Sections, when washed in water 

 for a coujile of minutes after staining, have a purple or lilac colour , 

 the staining also is less difiuse, and more confined to the nuclei, than 

 in the case of the ordinary solution of carmine, or picrocarmine. It 

 also has the advantage of not overstainiug even if a section is left in 

 it for a whole day, and if it dries up by evaporation (in a watch-glass 

 for instance), the addition of a little water will render it once more 

 ready for use — no precipitate being produced. It is advisable to add 

 a few drops of some antiseptic, such as carbolic acid, to the solution : 

 it will then keej) for years. 



2. Borax-carmine. — A 1 to 2 per cent, aqueous solution of borax is 

 boiled with i to f per cent, of powdered carmine. To the dark purple 

 solution acetic acid is continuously added, drop by drop, with con- 

 stant shaking, until a bright red colour is attained. It is then 

 filtered, or, as it filters very slowly, allowed to stand, and decanted. 



Tliis solution stains sections very rajiidly, in from ^ to 3 minutes, 

 but quite uniformly. If, however, they are washed with water, and 

 placed in a watch-glass of 50 to 70 per cent, alcohol, containing a drop 

 of hydrochloric acid, the colouring matter is removed from all parts 

 of the tissue except the nuclei, which remain deeply stained. 



3. Alcoholic-carmine. — To 50 cub. centim. of strong alcohol (60 to 80 

 per cent.) 3 or 4 drops of HCl are added, as much powdered carmine 

 as will lie on the point of a knife is added, and the whole boiled for 10 

 minutes, and filtered when cold. The exact projiortion of carmine 

 and acid depend upon the quality of the former. If a section placed 

 in the fluid stains in 5 to 10 minutes uniformly, there is not sufficient 

 acid, and more must be added. If after standing for some days the 

 solution acquires a yellowish-red colour, too much acid has been 



* 'Arch. Mikr. Aiiat.,' xvi. (,1879) p. 463. 



