2-42 Mr. W. Reckitt on the Preservatiun 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 entu'ely 

 unfitted for exhibiting the structui'e of vegetable tissues, as well 

 as the dehcate parts of insects, fi-equently 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. "NY. Griifith. Consequently I set to work on the 

 plan proposed by that gentleman, but was much disappointed at 

 the length of time wdiich 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 di-y- 

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

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

 a di'uuken 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 ensm-e it drying speeddy. 



The object should be mounted in a cell in the way 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 exposm-e 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 ch-y in, when the slider may be papered. 

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



