The Microscope. 195 



factory results in matters of this sort requiring a little manipu- 

 lative skill mixed with a modicum of common sense. The 

 remedy is a plain one, and lies within the reach of every one of 

 yon who have met with these disappointments. Look to it first 

 that you have a good cement. It will not answer to proceed as 

 one gentleman told me he had done in making zinc cement, and 

 which, though it looked all right, was of no account as a ce- 

 ment. He put "a dime's worth of white zinc and a dime's 

 worth of damar into about a quarter's worth of benzol and 

 shook them up together until the damar was dissolved." You 

 must take pure, dry zinc ozide — and to make sure it is dry you 

 had better heat it in a muffle for a little while, and rub it up 

 with damar dissolved in benzol in definite proportions. When 

 finished there should be about as much zinc as there is of the 

 damar solution. Make your cells with this, and let them dry 

 thoroughly before using them. How long should they dry? 

 You can set no fixed time. The period will vary according to 

 the thickness and size of the cell, the weather, and the season 

 of the year. The benzol evaporates much faster in hot, dry 

 weather than in rainy or cold weather. They should be left until 

 the thumb nail pressed upon the edge of the cell leaves no in- 

 dentation. Try this plan once, and my word for it you will have 

 no cause to complain of leakage or creeping of glycerine. 



Dr. Stowell said that he desired to indorse every word that 

 Dr. James had uttered. He believed that zinc cement was the 

 best cement ever devised, and the only one that should be used 

 with glycerine. Some might ask wdiyuse glycerine at all. He 

 would answer, because that for certain kinds of histological 

 work it has no equal. If the cells are built with zinc cement, 

 and allowed to dry thoroughly, as Dr. James suggests, there will 

 be no complaint on the score of leakage or creeping. Mr. Cole, of 

 London, whose slides are peerless, uses nothing but zinc cement. 

 Mr. Walmsley, of whose mounts the society was abundantly 

 able to judge, since some of them are in every cabinet, and are 

 unequaled in beauty of finish and durability, uses nothing but 

 zinc cement. 



Mr. Walmsley desired to be put on record as indorsing all 

 that Dr. James had said. He had used the cement, made as 



