Journal 



OF THE 



NEW-YORK MICROSCOPICAL SOCIETY. 



Vol. II. FEBRUARY, 1886. No. 2. 



THE BEST COVER-GLASS CEMENT. 



BY DR. L. HEYDENREICH, OF ST. PETERSBURG. ^ 

 {fiead Dec. \%th, 1885.) 



The best cover-glass cement should be : — 



I St. Absolutely hermetic, and should not, under any circum- 

 stances, require renewal every year. Two or three coats of the 

 cement, applied at short intervals after an object is mounted, 

 should permanently secure and preserve the object. 



2d. It should be as hard as ^iass, or, if possible, harder. 



3d. It should not crack nor become detached, and should be 

 so solidly adherent as to be less likely to break than the glass 

 to which it is attached ; and 



4th. It should be insoluble in water or glycerine, or in any 

 liquid used as an immersion medium with objectives. 



Notwithstanding the large number of cover-glass cements al- 

 ready known and in use, I think another should be sought for, 

 one which shall conform to the foregoing requirements. That 

 all do not so conform is evident when we hear of the damage 

 caused by the use of cements which fail in effectually preserv- 

 ing microscopical preparations, some of which preparations are 

 of considerable value. As an instance of such damage, I 

 mention the case of the fine collection of nerve-tissues belong- 

 ing to Jakubowitsch. 



We have commercial varnishes which are very hard and 

 durable. Some of them, used in the finishing of carriages, are 

 found, after the lapse of a year, to be in the same condition as 

 when first applied. The varnish used on tin pans in Albumen- 

 factories remains unchanged for a year, although subjected daily, 

 for many hours, to a temperature of 100° R. These and similar 



iTraaslated by E. A. Schultze, from Zeitaohrift fUr Wiasenachaftliche Mikrosko- 

 pie, VoL n., pt. 8. 



