104 TllK AMKI{I(\\N MONTHLY [ Ai>ril, 



Mi'IIumI of DtMiioiistnifiiiu; Livinu: Tricliiiiai'. 



n\ .\i.(.i:kki)n s. harni:s Ik.. m. d. 



ST. LOUIS, M. 



Thf livinjj; tiicliina. or pork worm, ni;ikcs ;iii attractive slide, 

 aiul never fails to attract attention. An olil cat or rat is killed, and 

 the imiscle Ironi between the rihs, also the dia|)lira<;ni and 

 muscles of" the thijjh. .-ire extirpated. A piece is nipped from 

 or.ch ot the specimens, and placed between two slides, which are 

 pressed tojjether antl examined under the microscope with about 

 a one-inch objective. 



It' the tnchin;c are found to be present in their cysts, a piece 

 of* the muscle the si/e of a pea is placed in the lollowinof solution 

 in a small bottle : 



IVpsin, .... <x\. I I I 



Water. . . . . ." i i 



1 1\ (hochloric acid, m. ii 



As this is to duplicate the jirocess of' dijjestion, the fluid must 

 be kept at bodv temperature, pref'eiably in the j^ants pocket, or 

 in a warm oven. The fluid is to be shaken everv little while ; 

 in about three hours, sometimes less, the meat will be dissolveil, 

 as well as the cyst which contains the trichina-. The fluid is 

 then poured into a conical-shapeil »;lass to allow the trichina? to 

 .settle to the bottom, which operation will consume about ten 

 minutes. A pipette is then introduced into the j^lass near the 

 bottom, and the contents placed in a glass cell, which should be 

 large. This cell is then placed under a dissecting microscope, 

 and the trichina; taken out by means of a pipette and placed in 

 clear water. They are again picked out of the clear water by 

 the same method, and placed in a drop of pure water in the 

 centre of a glass, cement cell, or in a live-box, and a few minutes 

 allowed for the worms to settle to the bottom. A cover is now 

 put on and sealed with white vaseline. It is now ready for examina- 

 tion on a hot stage under the microscope, where the worm may 

 bv enlivened at will bv the heat. 



I have found that about three trichina- in a cell are sufficient, 

 for when thev get livelv they are hard to keep in the field and in 

 focus. If a permanent mount shoulil be wanted of isolated worms 

 they are finally placed in a drop of glycerin instead of water in 

 a cell and sealed with cement. The worms will be found 

 uncurled in the givcerin, which kills them. 



The meat may be kept in pure glycerin for several years, but 

 of course the worms will be dead and may be dissolved out by 

 this process. 



An Aluminum Microscope, — A microscope recently made 

 of aluminum weighs onlv 2 poimds lo^ ounces. The screws are 

 of brass, the fine adjustment of steel, and the nose-piece of German 

 silver. The same instrument in brass weighs 7 pounds 13 ounces. 



