184 THE AMERICAN MONTHLY [August, 



killing must be instantaneous in of der to have the animal in an expanded 

 state, without which it would be pi'actically worthless. This may be 

 done by any of several reagents, among the most successful of which, 

 in my own experience, have been corrosive sublimate, saturated solu- 

 tion in water ; Lang's fluid, which is essentially the same, with addition 

 of small per cent, of acetic acid ; osmic acid ; picric acid. I have named 

 them in the order of my preference. In the second they must be left 

 but a few moments, as the acid disoi-ganizes the structure. The same 

 may be said also of the latter two. After killing it is only necessary to 

 harden the protoplasm by the ordinary method of alcohol of increasing 

 strength, then to stain them with borax carmine, or other if preferred ; 

 then complete the process by dehydration with absolute alcohol ; finally, 

 to render transparent with oil of cloves or other appropriate I'eagent, 

 and mount in balsam. 



It should be noted that great care is necessary in transferring from 

 one medium to another that the specimens are not lost. This I have 

 avoided by using the thread syphon and working with great patience. 

 I have by this method secured beautifully stained Amoebae naturally 

 expanded and exhibiting almost every phase of their life-history. I 

 have also fine specimens of paramoecia and hydroid medusae, etc. Vor- 

 ticella I was not able to get fully expanded, though otherwise excellent. 



While the method is somewhat tedious, it is not more so than kindred 

 methods of preparing diatoms and such like organisms, and will in re- 

 sults repay richly, I think, anyone who will take the pains to give a 

 few trials. 



I should have noted also that the final mounting may be done with 

 equal success in glycerin or glycerin jelly. In a word, after the pro- 

 cess of preparation the mounting may be done by any of the ordinary 

 methods. 



Miami University, "July 10, '89. 



The Bidwell Cabinet. 



By W. D. BIDWELL, M. D., 



LEAVENWORTH, KAN. 



During a recent attempt to provide for the storing of microscopic 

 slides, I became convinced that none of the cabinets I had seen were as 

 simple and convenient as could be made, and accordingly I devised the 

 Bidwell Cabinet. No attempt will be made to patent it, and I freely 

 allow all persons to make them for their own use, if, indeed, they have 

 not used them already. Prof. Lighton informs us, however, that he has 

 seen every style yet made, but none like this. The drawers contain 12 

 slides each, and are made of a single piece of seasoned black walnut 

 7^- inches by 8 inches and § of an inch thick. 



The compartments are made with a one-inch chisel, making six cuts 

 \ inch apart and £ inch from the side on each side and then cuts corres- 

 ponding to these three inches toward the middle of the drawer. Then 

 a piece is easily chipped out between each pair of cuts, leaving 12 

 drawers, which easily hold the slides, separated down the centre by a 

 ridge f to 1 inch wide. Taking a single cut with a gouge out of this 

 ridge opposite each trough makes a convenient place to slip in the 



