1888.] MICKOSCOPICAL JOUKNAL. 29 



bedded in soap mixture (/. e., soap dissolved in alcohol and mixed with 

 glycerin). 



The following formulae for the preparation of logwood stains are given in 

 Dr. Sterling's 'Text-book of Practical Histology' (London: Smith, Elder 

 & Co.) :— 



ist. A. Dissolve .3 grns. of hgematoxylin in 10 cc. of absolute alcohol. 

 B. Dissolve .3 grns. of alum in 100 cc. water. A few drops of A added to a 

 few cc of B. give a solution of a beautiful violet color, which rapidly stains 

 tissues. 



2d. Take 60 grns. of extract of haematoxylin and iSo grns. of alum ; rub 

 them together in a mortar, and slowh^ add 280 cc. distilled water. Filter, 

 and to the filtrate add 20 cc. of absolute alcohol. 



LOGWOOD SOLUTION FOR RAPID STAINING. 



This solution, devised by E. A. Cook, yields good results, but it has no 

 advantages over any of the above. The ingi-edients are extract of logwood 

 and alum, of each 6 parts, cupric sulphate i part, and water 40 parts. Grind 

 in a mortar the alum, logwood, and cupric sulphate, all of which must be 

 iron free, and when powdered add sufficient water to form a thin paste. 

 Leave this for one or two days, then add the remainder of the water, and 

 filter. To the filtrate add a crystal of thymol, to preserve it from mould. 

 For tissues hardened in chromic acid add 8 drops of this solution to 120 drops 

 of water, and add one drop of a tenth per cent, solution of potassic bichro- 

 mate just prior to use. 



DR. BEALE's carmine FLUID FOR STAINING GERMINAL MATTER. 



Next to logwood stains maybe placed the difterent preparations of carmine. 

 These w^ere much used by the older microscopists, and are still extensively 

 employed on the Continent ; though in many cases they have been given up 

 in preference for logwood and anilin stains, which are not so trying to the 

 eyes. 



Carmine, 10 grains. 



Strong liquor ammonia, ^ drachm. 



Price's glycerin, 2 ounces. 



Distilled water, 2 ounces. 



Alcohol, ^ ounce. 

 The carmine is to be dissolved in the ammonia with the aid of heat and 

 the glycerin, water, and alcohol added after. 



Dr. Beale says: — 'The rapidity with which the coloring of a tissue im- 

 mersed in this fluid takes place depends partly upon the character of the tis- 

 sue and partly upon the excess of ammonia present in the solution. If the 

 solution be very alkaline, the coloring will be too intense, and much of the 

 soft tissue^ or imperfectly developed formed material around the germinal 

 matter, is destroyed by the action of the alkali. If, on the other hand, the 

 reaction of the solution be neutral, the uniform staining of tissue and germinal 

 matter may result, and the appearances from which so much may be learnt 

 are not always produced. When the vessels are injected with Prussian blue 

 fluid, the carmine fluid requires to be sufficiently alkaline to neutralize the 

 free acid present. The permeating power of the solution is easily increased 

 by the addition of a little more water and alcohol. In some cases the fluid 

 must be diluted with water, alcohol, or glycerin ; and the observer must not 

 hastily condemn the process, or conclude, as some have, that a particular 

 form of germinal matter is not to be colored, until they have given the plan 

 a fair trial and tried a few experiments.' 



