90 MICROSCOPICAL TECHNIQUE. 



down see that it is central, and put on a spring clip ; a little balsam 

 will ooze out in five or six drops around the cover ; lay it aside to 

 harden. In about a week's time take off the clip, put the slip on 

 the turn-table, and if the cover has moved, or is not central, push 

 on the excentric side, then put on the clip, and in a week's time, 

 provided care is used in handling, the overflow of balsam can be 

 removed and the mount cleaned around the cell (I do all this work 

 on the turn-table), and a seal of shellac varnish put around it. 

 This cries quickly, and the following evening it can be ringed with 

 King's Scarlet, Brunswick Black, or some other cement. When 

 the second coat has dried hard, ring again. A finishing coat may 

 be put on, but I find it best to wash the mount well in soap and 

 water, using a tooth-brush as a scrubber, before putting on the last 

 finishing touches. . . . Before putting the balsam in the cell, 

 cut four notches, equidistant apart, through the cell, large enough 

 for a fine needle to pass through, then proceed as above. These 

 notches are for the purpose of moving or adjusting the object in 

 the cell ; also to allow for the shrinkage of the mountant. If the 

 object is not central, a fine needle or wire, or a stiff bristle, can be 

 pushed through one of the notches and the object moved to suit 

 the eye. 



Neutral Red.*— According to Prof Ehrlich this new pigment is 

 excellently adapted for biological researches and vital staining, as 

 it possesses a striking affinity for living tissues. If tadpoles be 

 placed in solutions of i/io,ooo up to 1/100,000, the animals become 

 stained in quite a short time, and during the first and second day 

 of their immersion absorb so much of the pigment that all their 

 tissues become dark red. The pigment may be seen in the cells 

 as minute granules. Larger animals may be subcutaneously 

 injected, and even feeding with the pigment gives good results. 

 In germinating plants the author obtained successful staining 

 results, and by combination with other pigments — e.g., methylen 

 blue, etc. — a double or triple staining. 



Ehrlich's Triple Stain. f— Dr. G. Reinbach gives a formula for 

 the triple stain, as improved by Ehrlich. The author used it for 



* Allgem. Med. Centraheit., 1894, vide Joum. R.M.S., 1895, P- 128. 

 ■\ Arch.f. Klin. Chirurg., XLVi., vide Joum. R.M.S., 1895, p. 129. 



