HA RD WICKE'S SCIENCE- G OSS/r. 



2 5 



ON MOUNTING PATHOLOGICAL SPECIMENS. 



By V. A. LATHAM, F.M.S. 



z^m&<S&g$\ ORBID specimens 

 "~l«^?JlP can be prepared in 

 the same manner 

 as normal tissues, 

 by the ordinary 

 processes which are 

 well known to all. 

 The subject will be 

 treated under the 

 following heads : — 

 (i.) Examination 

 of specimens while 

 fresh. 



(2.) Hardening 

 of same. 



(3.) The making 

 of sections. 

 (4.) Staining. 

 (5-) Preservation 

 by mounting. 

 It may here be observed that specimens of morbid 

 tissues require, as a rule, a shorter immersion in 

 chromic acid solution than healthy tissues do. A 

 very small degree of over-hardening speedily renders 

 them useless. 



(1.) Examination of fresh tissues. 



Divide the tissue into very thin slices with a section 



knife (should it prove too friable, tease it out by 



means of mounted needles). Be careful to use a 



. well-wetted knife, and make your slices rapidly, or 



they will be too jagged. 



Now wash your fresh slices well in water (when- 

 ever water is used it is distilled in every case), and 

 then immerse it in any normal fluid, such as a 

 solution of chloride of sodium to the proportion of 

 f per cent, in water, i.e. *]\ parts in 1000 parts 

 aqua dest. by measure, or (1) aqueous humour taken 

 from the anterior chamber of the eye of a newly 

 killed ox. (2) Serous fluids, such as taken from the 

 pericardial sac, or amniotic fluid. To either of these 

 serous fluids iodine may be added to form iodised 

 serum. It is prepared by adding 1 part tinct. of 

 iodine to 100 parts of the serous fluid. 



To each oz. of the fluid add a couple of drops of 

 No. 254.— FEBRl ARY 1886. 



cai >olic acid and filter. Its disadvantages are that it 

 alters the tissues slightly, and stains them yellow. 



Glycerine is frequently used in preference to the 

 salt solution, and is specially applicable to the 

 examination of membranous specimens which only 

 need spreading on a wet glass slide, and then covering 

 with the same. Portions of the renal, pulmonary, 

 and hepatic organs are thus frequently examined. 

 Also portions of tumours ; their friability, however, 

 requiring them to be teased out with needles as sug- 

 gested above. The same may be said of portions of 

 the heart's muscular tissue. 



(2.) Hardening : — There are several hardening 

 agents in use, viz. : — 



(a) Midler's fluid : — R. Potassium bichromate, 2 

 parts. Sodium Sulphate, 1 part. Aqua, 100 parts. 

 Dissolve. 



The tissue should be kept in this solution for from 

 one to two weeks, then placed in common alcohol for 

 two or three days, after which it is ready for making 

 sections. It is a valuable fluid for maceration of 

 tissues which are examined by teasing — as tumours, 

 muscle, &c. 



(P) Chromic acid J per cent., 15 grs. to oz. Take 

 of this 2 parts, and sp. vini meth. (methy. sp.) 

 1 part. Stir. 



Allow at least 8 or 10 oz. for your specimen, and 

 be very careful not to allow it to remain in the 

 solution more than a week. Change the solution 

 once or twice in this period ; be careful to cut the 

 specimens in small pieces before immersion, and 

 after hardening, let them steep 24 hours in alcohol 

 before cutting specimens. 



(7) Bichromate of potash : — 2 per cent. It is 

 useful for blood-vessels, nerves, kidneys, ovary, and 

 especially for brain and spinal cord. When using, 

 leave the specimen for at least a fortnight in the 

 solution, changing it every three or four days. 



(5) Alcohol is also of use for spleen, testis, and 

 lymphatic glands. It is specially worthy of note, as 

 being a necessary complement in many cases to 

 induration by other agents (Muller's fluid, bichromate 

 of potash, &c), a couple of days' immersion in alcohol 

 being frequently indispensable to completely secure 



c 



