INVERTEBRATA, CRYPTOaAMIA, MICROSCOPY, ETC. 1039 



the object dried on it, and the two are held together by the forceps 

 and gently warmed ; this serves to attach the ring to the slide and 

 cover at several points, so that the forceps may now be laid aside. 

 The next step is to take a glass slip (another slide), and laying this 

 on the cover, to grasp the two slides at each end by the finger and 

 thumb of the two hands, and pressing them tightly together, to warm 

 the slide gently ; by looking at the ring obliquely on the under side 

 one can tell at once when all the air is pressed out, and the adhesion 

 is complete between the cover and the ring, and also the ring and the 

 slide, and they must be held together a moment or two to cool. If 

 the lac is sufiiciently thick on the paper, the adhesion takes place 

 quickly, and with moderate heat, and there will be no danger of 

 breaking the cover, unless it has been warped in the process of warm- 

 ing, which will sometimes occur when very thin glass has been heated 

 too much for the purpose of burning off the organic matter, or when 

 the su2)port is too small in diameter, or when it is not flat. 



The author, in conclusion, says, " I cannot conceive of anything more 

 satisfactory than these rings. IMany largo objects which would be 

 crushed if one used only the shellac rings made on the slide by the 

 use of the turntable, by the giving way of these by softening, and 

 under the necessary pressure for attaching the cover, are perfectly 

 protected by the paper rings. I am satisfied that the balsam mounts 

 will be much less frequently used as soon as we can find some sure 

 dry process. The diatoms as a rule show much better when mounted 

 dry, and with whole frustnles, exhibiting both the side and the front 

 view, also the mode of attachment, &c. The dry mounts are certainly 

 to be preferred when they are desired for anything except pretty 

 objects, and even for this latter purjjosc there is often a very great 

 difference in favour of the dry mount. Although I have not used 

 these shellac paper rings for any very great length of time, yet I can 

 see no reason why they should not be equal to the simple shellac ring 

 for durability, and very much superior to it in other respects." 



We should note, in regard to this suggestion of Prof. Hamilton 

 Smitli, that the rings above referred to were the subject of a paper 

 read to this Society by Mr. James Smith* in 18()5. 



Dr. Phin has found, he says,t "that pure shellac in all its forms 

 is very apt to separate from the glass after a time. 



Wax Cells. :J: — Dr. Phin does not appear to be disposed to abandon 

 these cells, as suggested by their originator (Prof. Hamilton L. 

 Smitli). He has carefully examined a number of slides of the mounting 

 material of which wax forms a part. Some were found to be spoilt, 

 others were good. It is- evident that the dew may arise either from 



* 'Trans. Micr. Soc. Lond.,' xiv. (18GG) p. 29. The following is nn extract 

 from Mr. Jnnies Smitli's proper: — "lUitli surfiic-c8 of the rnrdboanl [are to he] 

 coveri'd willi a cciuiiit turimil of whcUac or niaiiiic j^hir di.sscdvi'd in naplitha ; 

 onu to Ihrou cuutinj^s of this ceiiunt Ix-iii^ u.sually sullifirnt, cure hcinf: tnkcu 

 that one ia perfectly dry lioturo the next is iipplied. The cells hi iug tlius pre- 

 pared, tlicy Clin be cnt oil", and by the ap|dication of heat and slight pressure are 

 easily attached to a class slide." 



t * Am. Journ. Micr.,' v. (IS.s(l) p. WX X Ibid. 



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