NOTES AND CORRESPONDENCE. 



Microscopy. — When mounting objects in fluid, I have used 

 for a long time, a simple contrivance, which, as I have seen 

 it nowhere described, and as it is so simple and useful, seems 

 worthy of a note. Its use is for holding the thin glass cover 

 firm, when applying the cement. 



I make it of a piece of hoop-spring, about three inches 

 long, heating and bending into a large curve, to approxi- 

 mate the ends, as in Fig. 1. The lower arm, A B, should 



Fia.l. 



be quite straight, and the curve should not project below its 

 level ; the end A should project a little beyond the end C, 

 that it may catch under the edge of the slide in applying it. 

 The arm C D should not be quite parallel to the arm A B, 

 but so inclined that when applied to the slide (see Fig. 2) the 

 thickness of the slide will bring them parallel. The arm 

 C D must be quite short, so that it shall not occupy more 

 than half of the thin covering glass. The large curvature 

 allows the cement to be applied quite round the cover. It 

 may be tempered to suit — some stiff", others more flexible. 

 One can be made in five minutes ; and, to me, they have 

 proved very useful. — T. F. Allen, M.D., New York. 



