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



whole thing is placed in tiirpentine. This washes out the clove oil 

 and fixes the objects very firmly to the paper. When submerged in 

 tiirpentine, if desirable, the relation of each object to the orienting 

 lines can be redetermined under the Compound microscope with greater 

 precision than before. If any one of them has been inaccurately placed, 

 it may still be moved to some extent, but it is better to note the fact, 

 and make the necessary deviations from the section lines, when that 

 particular object is sectioned. 



The paper with the attached objects is now placed in the paraffine 

 bath, and finally removed and covered with paraffine in the usual way. 

 After cooling in water the block is trimmed and the paper peeled off, 

 leaving the objects in the paraffine, close to the under surface of the 

 block. This surface is now marked by the orienting lines of the ribbed 

 paper and also by the record numbers which, before imbedding, were 

 written with a soft pencil on the paper. The block is now fixed in the 

 microtome and the objects cut one after the other as though a Single 

 object had been imbedded; or a number of them may be cut together, 

 if they have been arranged with that object in view. For example 

 we may use a thinner collodion and arrange a large number of insect 

 embryos, or small worms, in a compact bündle, like a package of 

 cigarettes, and cut them all at once. 



Although I have not tried Dr. Woodworth's method, it seems to 

 me that to what is described above he has merely added several com- 

 plications which might in most cases be omitted. He gums the paper 

 to a glass slide, dries it, Covers the exposed surface first with a layer 

 of gum and then with a collodion film, each of which must dry sepa- 

 rately. The objects, cleared in turpentine, are then placed in position 

 on the film, which is softened and rendered adhesive by exposure to 

 ether vapor; then slide and all are placed in the paraffine bath. 

 Finally, after imbedding, the slide is soaked in water to free it from 

 the paper, and the paper from the paraffine. Now I find it quite 

 unnecessary to gum the paper, as with most objects it comes away from 

 the collodion and paraffine very well without it. It is moreover very 

 inconvenient and unnecessary to imbed the paper attached to a glass 

 slide in the paraffine bath. The paper alone can be handled with 

 perfect ease, and it does not curl up or warp in the bath. If any 

 warping occurs, I should say it was due, for various reasons, to the use 

 of a collodion film, in place of minute drops of collodion and clove oil. 

 I should suppose also that any object of considerable size, say the 

 egg of Limulus, could not be easily fixed in the mauner suggested by 



