50 THE MICROSCOPE. 



i^cTcc lions. 



Methods of Hardening Material for Microscopic Sec- 

 tions. — It is the object of the present paper to point out briefly, 

 a tew hints which may be serviceable in the manipuhitions and. 

 preservation of morbid growths in connection with their microscopical 

 examination, in order to determine correctly their histology. I 

 may at the outset remark that it is impossible to make a micro- 

 scopical examination of any tissue or organ which has not been sub- 

 mitted to a process of hardening, and that this process usually re- 

 quires from eight to ten days, according to the nature of the tissue 

 and the character of the regents used. I deem this remark neces- 

 sary, inasmuch as I frequently have had very excellent medical 

 practitioners leave me growths or large tumors to examine micro- 

 scopically, and call next day for results. 1 will consider the best 

 means for hardening the various growths according to their posi- 

 tions, or the tissues with which they are connected. 



Morbid conditions of the skin, including growths from sub- 

 cutaneous tissue which invade the rete milpighii, epithelioma, etc., 

 of skin. For these growths I find the best fluid for general use is 

 methylated spirit. Dilute spirit in the proportion of two parts 

 spirit, to one part water being employed for the first three days, and 

 then the fluid changed, an:l ordinary methylated spirit substituted. 

 When I say the tumor is to be placed in spirit, I do not mean that a 

 large mass of epitheliomatous cancer is to be simply tiirown into 

 spirit and left there for a week, but that the growth must first be cut 

 into pieces about one inch squ.ire and these placed in the spirit — this 

 is to allow the flui'l to permeate all parts of the tissue, and thus 

 preserve them in an equal degree of freshness; this is an important 

 step and one usually forgotten. 



I remember on one occasion having had sent to me by Dr. 

 Hughlings Jackson, an adult human brain, where death had taken 

 place during an attack of chorea — the object being that the corpora 

 striata and optic thalami might be searched for embolism. The 

 brain was preserved entire in spirit, the result of the preservation 

 being that the central parts were all rotten and hence a very valuable 

 specimen lost. If a small portion only of a tunnjr is kept for exam- 



