Method of Preparing Delicate Organisms. Bij E. Lovett. 789 



ceases, take a clean cover-glass and breathe upon the side intended 

 to come into contact with the fluid, thus enabling it to flow evenly 

 without inclosing air-bubbles ; press the cover-glass very gently 

 into the cement, which will cut through the fluid, and attach the 

 cover firmly. Then remove the superfluous fluid by means of a 

 large camel's-hair brush, and lay aside for a few minutes to set, 

 when a stiff" coat of the same cement should be applied to the junc- 

 tion of the cell to the cover-glass. 



In about a week this structure will have become so hard and 

 tough, that nothing short of actual unfair treatment will damage 

 it, and it may be finished off" with such varnishes as fancy may 

 dictate. 



I have submitted specimens of my work to the most severe 

 tests, with certainly more satisfactory results than would have been 

 the case with an ordinary balsam or even dry mount. 



I inclosed some slides, prepared in this manner, in a tin box, 

 and buried them in frozen snow for twelve hours, from which I had 

 to cut the box out with a chisel ; I then placed them in an oven 

 and submitted them to a dry temperature of 140° F. for four hours, 

 at the end of which time the slides exhibited no change or dete- 

 rioration. The cement itself, when once hard, is so exceedingly 

 powerful, that, as before stated, a metal cell affixed by it to a 

 polished slip can be filed completely away with a heavy coarse file 

 without loosening the cement in the slightest degree : its advantage 

 in being insoluble in the fluid used is also obvious, and I am sur- 

 prised that it has not been more generally adopted by microscopists, 

 considering its vast superiority over marine glue, or, in fact, over 

 any cement in ordinary use. 



The fluid itself, by judicious admixture of various proportions 

 of alcohol, glycerine, and water, can be used satisfactorily for the 

 preparation and final mounting of Fishes, Mollusca, Crustacea, 

 Echinodermata, Insects, Arachnida, and Plants ; many of the most 

 delicate of which could not retain any form whatever in a dried 

 state, and would be simply ruined in balsam. 



I hope, therefore, that I have been able to show how such 

 delicate organisms may be preserved for microscopic examination 

 in a comparatively simple and easy manner ; and as so much atten- 

 tion is just now directed to the very important question of our food- 

 supply as derived from the ocean, there can be little doubt that 

 the study of the early forms of life of our edible fish, mollusca or 

 Crustacea, is one of the most useful and valuable to which the 

 microscopist can possibly devote his attention. 



