1876.] : Microscopy. 57 
brain, cells are met with of such various shapes and sizes. Another 
great deficiency in the carmine-stained sections was the indistinctness of 
the fibres. In all cases along time was required for the carmine to take 
any effect, sixty to seventy hours being insufficient to stain deeply. 
Hematoxylin produced much more successful results. In the first 
place, the fibres were almost always brought out distinctly ; and secondly, 
the cells with their processes were in many cases clearly defined. But 
still the cortical substance was frequently insufficiently stained, even after 
twenty-four hours’ immersion in the staining fluid, which, owing to the 
use of alum, is sufficient to render the preparations too brittle to be easily 
mounted. The special value of hematoxylin consists in the clearness with 
which it brings out the nuclei of the medullary substance, and the fibres 
and cell-processes of the cortical substance ; its fault is a want of depth 
in the color of the cortical substance. 
Having found aniline blue useful for staining some hardened tissues, I 
was led to try it in this case. The only virtue that it had was that it 
stained the protoplasm of the medullary cells very darkly, and always 
attacked them first; that is to say, its strongest point exactly agreed with 
the weakest point in hematoxylin. 
This led me to double staining, and the results were fully up to my 
expectations. The following is the method of staining which I finally 
adopted. After from twenty to twenty-four hours’ immersion in hema- 
toxylin I washed the preparation in weak spirit, and then in distilled 
water till all the spirit was driven out.. I then immersed it in aniline for 
from half to three quarters of a minute, again washed it in spirit, and 
after the usual treatment mounted it in Dammar. 
The preparation of hematoxylin used was that recommended by Frey, 
te, a few drops of an alcoholic solution of the pure crystals added to a 
solution of alum in water. The latter I have used in the proportion of 
from two to four grains of alum to an ounce of water. The more alum 
there is in the solution the more rapid is the staining, but there is great 
anger of making a thin section too brittle by the use of muchalum. The 
aniline I diluted sufficiently to be able to see through it pretty easily. 
The results obtained by this method are most satisfactory. The nuclei 
already stained by the hematoxylin are made of a richer color, while the 
protoplasm surrounding them is much bluer than the nuclei themselves- 
Tn the cerebellum the effect is particularly good, the medullary substance 
being of a rich purple and the cortical substance of a pale blue, but show- 
ing the cells with remarkable clearness. — W. H. Poore, in Quart. 
Journ. Mic, Science. 
. Use or Carpotic Acb In Mountine.— Mr. T. Barnard, of Kew, 
Melbourne, communicates to Science Gossip a reassertion of the suc- 
cessful use of carbolic acid as a substitute for turpentine in mounting 
Mséct dissections. A portion of the insect, fresh, is washed, soaked for a 
ew hours in pure carbolic acid, and then mounted in Canada balsam with 
