242 Mr. W. Reckitt on the Preservation of Objects 



XXIX. — On the Preservation of Objects of Natural History for 

 the Microscope. By William Reckitt, M.R.C.S.L. 



To R. Taylor, Esq. 

 Dear Sir, 

 Having read in the present Number (February) of the 'Annals' 

 a paper by the Rev. M. J. Berkeley on the mode of mounting 

 objects of natural history for the microscope, I am induced to 

 offer for your perusal a few remarks on the same subject, and to 

 suggest to you what appears to me a surer and a better plan. 

 For the last few years I have been engaged in microscopical in- 

 vestigations, during which time I have frequently had occasion 

 to regret that many of my best preparations were rendered en- 

 tirely useless by preservation in balsam of Canada, the only me- 

 thod of mounting with which I was acquainted, which was entirely 

 unfitted for exhibiting the structure of vegetable tissues, as well 

 as the delicate parts of insects, frequently converting them into a 

 confused hyaline mass, in which nothing of their structure was 

 recognisable. 



In the spring of last year I requested the publication of a few 

 remarks on the best mode of mounting in the ' Annals,^ which 

 was answered obligingly by the appearance of a paper on the 

 subject by Dr. J. W. Griffith. Consequently I set to work on the 

 plan proposed by that gentleman, but was much disappointed at 

 the length of time which was necessary to allow them to dry. I 

 then made a variety of experiments to invent a varnish which 

 would present the two grand desiderata of perfect fluidity, al- 

 lowing it to be easily applied, together with the property of dry- 

 ing quickly. All my endeavours to succeed in this would I be- 

 lieve have failed, had I not in my inquiries luckily stumbled on 

 a drunken painter, who suggested the employment of old black 

 japan. This, which can be obtained at any painter^s, I have used 

 ever since, and found to answer every expectation. It is abso- 

 lutely necessary that it should be old to ensure it drying speedily. 



The object should be mounted in a cell in the w^ay described by 

 the Rev. M. J. Berkeley, however minute it may be, as it pre- 

 vents the varnish from insinuating itself between the upper and 

 lower glasses ; the fluid should be soaked up to the margin of the 

 top glass by a small piece of blotting-paper, and then a very thin 

 delicate coating of black japan is to be applied with a fine camel- 

 hair pencil ; this will be perfectly dry on exposure to the atmo- 

 sphere in twenty-four hours, when another coating rather thicker 

 is to be applied, and on the third day another, which should have 

 two days allowed for it to dry in, when the slider may be papered. 

 I usually make a number of cells of different sizes at a time. 



