Production of Sections 263 



knives are not so useful for this purpose as the longer 

 patterns. 



In this method of section-cutting the object and the 

 knife must be kept continually wet, unless the object has 

 an oily consistency, such as some seeds, which may then 

 be cut dry. If an object is to be cut which has been 

 hardened or preserved in alcohol, then alcohol of the same 

 strength must be used for the wetting ; if the object has 

 not been in alcohol, then use dilute alcohol — say, 30 per 

 cent. — or distilled water. The wetting of object and knife 

 is best done with a small brush, not with a pipette, a drop 

 of the fluid on each being sufficient. Certain small and 

 smooth-surfaced objects may be held for cutting by being 

 cemented to a block of wood by turner's cement, made as 

 follows : 



Yellow wax ... ... ... 1 ounce, 



Eesin ... ... ... 3 ounces, 



mixed by melting, and used hot. 



The foregoing processes are essentially rough-and-ready 

 means of obtaining sections, and although they may serve 

 for the production of isolated or detached sections of certain 

 tissues, such methods cannot be called microtome methods. 

 It is impossible to cut sections thinner than about 20 /* by 

 these processes, even when every advantage is on the side 

 of tenuity. In the majority of substances suitable for such 

 processes it will be found difficult to exceed in thinness 

 40 /i. If sections of an organ are required immediately — 

 for purposes of diagnosis, for example — the freezing method 

 is practically the only process available. We do not, 

 however, recommend it for general work, as the sections 

 obtained by this method are not to be compared with those 

 made by the paraffin process. The freezing method, then, 

 must be looked upon as a special one, useful in cases of 

 emergency, but not to be relied upon as the best method 

 for general work. If the work is likely to necessitate 

 sections of tissues at the earliest possible moment for 

 special purposes, then an ether-freezing apparatus may be 



