374 SOME HARDEXIXG AGENTS. 



which can be laid on the use of strong alcohol. I have seen many 

 anatomical and pathological specimens which have been preserved 

 (?) in it, and on cutting them open after a year or two the odour 

 is very unpleasant, and shows decomposition, if not putrefaction, 

 to be present. Again. Sarcoma of the large-celled, and even the 

 spindle-celled variety may be readily mistaken for the small round- 

 celled, through the contraction produced. I think in Pathology 

 too much care cannot be taken in the examination of alcoholic- 

 hardened specimens. Always use a weak grade to begin with, 

 unless for some special reasons ; but remember to take the changes 

 into account. 



Alcohol should only be used in cases of rapid diagnosis in such 

 cases as require a report for immediate operation ; always, where 

 possible, harden some of the specimen in one, if not in two other 

 agents as well. It can be used for Bacilli in tissues if structural 

 changes are not to be regarded, and in some micro-chemical reac- 

 tions, possibly amyloid reaction. When distilled water is used to 

 examine these alcoholic specimens, the contraction is got rid of to 

 some extent by the tissues taking up the usual amount of water, 

 but this cannot get rid of the loss of transparency due to the 

 granular coagulated albuminates which will persist. Glycerine as 

 a clearing agent will aid this in some cases, or the acids and 

 alkalies, which dissolve the precipitated albuminates, though only 

 at the expense of many other structures. 



If fat is present, alcohol cannot be used. Lungs and muscles 

 do not harden well in alcohol, and sections kept in this country 

 for any length of time become very hard and brittle, and will not 

 stain well. Alcohol is best suited for hardening bacilli tissue, 

 salivary glands, and pancreas. 



According to our knowledge of hardening agents, I regard 

 their value in the following order : — First — Miiller's fluid and a 

 modification known as Erlicki's fluid ; Second — Chromic Acid ; 

 Third-Flemming's solution; Fourth-Rabl's fluid; Fifth-Perenyi's; 

 Sixth — Bichloride of Mercury ; Seventh — Kleinenberg's [solution ; 

 and lastly — Alcohol. 



