PREPARATION OF OBJECTS FOR THE MICROSCOPE. 149 



should record their experiences, thus giving us a literature on the 

 subject which shall be a guide to future operators for all similar 

 preparations. 



Now in regard to the mounting of double stainings ; balsam is 

 undoubtedly the best medium for all such as will bear this 

 mounting. An object mounted in Canada balsam is sure to im- 

 prove with age. If we can say of other media that they will 

 preserve their objects without change, it is the highest excellence 

 that can be expected from them. But a preparation in balsam 

 will be brighter and clearer the more the volatile elements are 

 evaporated from the medium that is, the older it is. It is how- 

 ever a fact that high refractive media, such as balsam and, less 

 so, glycerine, will obliterate, or render indistinct, the fine and 

 delicate markings of objects. There are very many vegetable 

 stainings which in balsam are without character or interest, but 

 which in carbolated or camphorated Water are veritable beauties; 

 all the fine cellular markings and the smallest hairs or glands ap- 

 pearing plain and distinct. I think it is safe to say that more 

 than half of the vegetable preparations you will have to do with, 

 if you exploit this field, will appear to better advantage in water 

 than in any other medium. 



So it has been quite a study with me for some time back to 

 find a means and a mode of fluid mounting both expeditious and 

 reliable. I am happy to say that I have found a method which, 

 so far as I can judge from the limited time that I have used it, 

 seems to be fully satisfactory. At least I have yet to discover 

 the faults of it. Our worthy member, Mr. Streeter, has been 

 lately making a very neat and ingenious set of punches by which 

 circular rings, five-eighths and three-fourths of an inch in diameter, 

 can be cut out of the colored sheets of wax used by the artificial 

 flower makers. Several colors of this wax are made in sheets 

 double thick, and if a still greater thickness is desired, two or 

 more sheets may be laid on top of each other. These rings, if 

 cemented in any way to the slide, make very convenient cells for 

 opaque mounting. But it occurred to me that if they were cov- 

 ered with a coating of some cement, such as marine glue, which 

 is unaffected by any of the liquids used for preserving objects, 



