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



Dr. WooDwoKTH. The adhesiveness of the small amount of turpeutine 

 011 the objeet seems to hold it in place. But the turpentine evaporates 

 rapklly and this would tend to free the objeet, or fill it with äir bubbles, 

 before the requisite number could be oriented, preparatory to softening 

 the collodion in the ether vapor. 



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

 pidity (although one need not hiirry), and accuracy of orientation ; tirae 

 saved in imbedding and sectioning a considerable niimber of objects as 

 one, and above all when many objects much alike are to be imbedded, 

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

 its appropriate number. 



* * 



As every one knows, it is a great niiisance to moiint under one 

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

 positioDs. It is often necessary to mount each one separately, and then, 

 at great risk, roll it about tili it is just where 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 collodion and clove oil close together in rows. An egg is then 

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

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

 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 collodion. 



The only precaution necessary in not to use too much collodion. 

 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 

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

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

 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 ara 28. Februar 1894.] 



