244 CEMENTS, VARNISHES, AND CELLS. 



unscrupulous niece of Cardinal Mazarin, who, when asked what 

 witchcraft she had exercised in gaining her mastery over the mind 

 of Marie de Medici, answered, " My only witchcraft has been 

 the influence of a strong mind over a weak one." 



Cemente, IDarniebea, an& CcIIe-* 



By H. N. Lyon, M.D. 



EVERY one who continues in a given line of work for a 

 number of years gradually confines himself to the use of 

 a few agents. It is especially so in microscopy, and in 

 these few remarks on cements, varnishes, and cells, I shall mention 

 only those that I have adopted, after having tried many and met 

 with many failures. 



I have selected this subject because, to me, it is of great 

 importance, and while I may not add anything to the existing 

 knowledge of the subject, my testimony may be of value in 

 helping to settle that vexed question as to what makes the best 

 cement, varnish, or cell. 



For some eight years I have been experimenting in this line, 

 and the experiment which finally settled the question, in my mind, 

 was made in an unexpected way. Some years ago I packed my 

 collection, numbering at that time many hundred mounts, in a 

 trunk, and took it with me on my wanderings. Altogether the 

 collection travelled between 15,000 and 20,000 miles, mostly by 

 rail. It fared badly, but I consider the loss as slight in compari- 

 son with what it taught me regarding the powers of endurance of 

 the various cements, media, etc. For obvious reasons it is 

 impossible to give exact figures and I can only give the general 

 result. There were only a few slides or covers broken, but the 

 number of mounts ruined by the covers coming off or separating 

 so that air entered was very large. The cements which stood this 

 test the best were gold-size and the solid marine glue. Balsam 



* From The Microscope. A paper read before the State Microscopical 

 Society, January nth, 1889. 



