XI, 1. Patten: Orienting small objects for sectioning, etc. 15 



Dr. WooDwoRTH. The adhesiveness of the small amoiint of turpentine 

 on the object seems to hold it in place. But the turpentine evaporates 

 rapidly and this would tend to free the object, or fill it with air bubbles, 

 before the requisite number could be oriented, preparatory to softening 

 the coUodion in the ether vapor. 



The advantages of the method, as I iise it, are many; ease; ra- 

 pidity (althoiigh one need not hnrry), and accuracy of orientation ; timc 

 saved in imbedding and sectioning a considerable number of objects as 

 one, and above all when many objects rauch alike are to be irabedded, 

 there is no danger of confusion, since each one is plainly marked with 

 its appropriate number. 



* * 



As every one knows, it is a great nuisance to mount under one 

 Cover a large number of objects that tend to roll about into undesirable 

 positions. It is often necessary to mount each one separately, and theo, 

 at great risk, roll it about tili it is just wliere we want it. And after all, 

 it is impossible to roll some things into place. I have used a modi- 

 fication of the method described above in mounting large numbers of 

 such objects under one cover, in perfect order and in any desired position. 



In mounting the eggs of Limulus, or heads of insect embryos etc., 

 I construct a cell of the requisite dimensions and place in it small drops of 

 the thick coUodion and clove oil dose together in rows. An egg is then 

 taken out of the clove oil, drained, and placed in a drop of coUodion in 

 the desired position. A great many eggs may thus be arranged Uke 

 serial sections under one cover glass. Before adding the baisam, the 

 slide is immersed in turpentine, which serves to wash away the clove 

 oil and leave the eggs more firmly fixed in the coUodion. 



The only precaution necessary in not to iise too much coUodion. 

 It is surprising to find the small amount necessary, and the firmness 

 with which the objects are held by it in place. 



I have recently used with a class of beginners the above method 

 of imbedding with satisfactory results — merely as a matter of convenience 

 [n manipulating small objects, easily soiled or broken in handling. Any 

 glazed paper, or even glazed trocing cloth, will do, provided the coUodion 

 and clove oil is thick enough. The raised ribs may be replaced by 

 fine black lines drawu with a soft pencil. These lines, like the numbers, 

 are transferred to the paraffine when the paper is removed. 



Hanover, N. H., Jan. 14, 1894. 



[Eingegangen am 28. Februar 1894.] 



