'^'^ The Mickoscope. 



much of the coarser work. 4. Dilute alcohol will not do. It should 

 have a strength of from 97-98 per cent, which, by the way, wiU 

 answer for all histological purposes. If the dilute article is needed 

 it can be made by adding distilled water to the stronger alcohol. 

 The formula for Mliller's Fluid is: Bichromate of potash, 2 parts; 

 sulphate of soda, 1 part; water, 100 parts. Rub the potash and soda 

 together, warm the water and add gradually, stirring till the salts 

 are dissolved. 



See now that the jars and bottles are thoroughly cleansed and 

 dried. In the bottom of each place an even layer of absorbent cot- 

 ton, say h inch in depth. This is done in order that the hardening 

 fluid may reach the under surfaces of the specimens lying on the 

 bottom. If this is not done specimens will oftentimes be found that 

 have become softened and consequently ruined. Now till several of 

 the jars about | full with undiluted alcohol, and two or three with the 

 Mliller's fluid, and they are ready for the reception of the specimens. 



It should be stated here that the process of first immersing the 

 specimen in dilute alcohol, recommended by most authorities, can- 

 not be advised. Alcohol hardens the material by (1) withdrawing 

 the water fi-om it, and (2) coagulating the contained albuminates. It 

 was, and is yet, assumed that if stronger alcohol be used from the 

 first, the specimen would contract so rapidly as to amount to violence, 

 and thus the various elements much distorted and displaced. This, 

 we believe, is a fallacy. A specimen hardened slowly will be found 

 (if not partially macerated) in exactly the same condition as 

 one hardened rapidly. By the latter method we not only eliminate the 

 danger of losing the specimen through maceration, but we avoid the 

 tedious and expensive necessity of changing the alcohol several times. 



Having procured a cat or other animal, fasten it to a narrow 

 table in the following manner: Take a piece of stout twine and 

 make a loop around a hind leg. Pass the twine under the table and, 

 bringing it up on the other side, loop the second leg. The animal 

 can be kept quiet during this time by setting it on the haunches. 

 Before it is put on the back make loops around the forelegs and 

 then press the animal back, at the same time tightening the anterior 

 cord by drawing on it under the table. Any unexpected moves (and 

 these are likely to be many if a cat is concerned) should be met 

 quickly and firmly. 



Have ready a paper cone, containing a sponge saturated with 

 chloroform. When the animal is well-fixed, clap this over the nose 

 and press down firmly. Watch the respiration carefully, for chloro- 

 form kills these animals quickly. When anaesthesia is complete, and 

 before death, make a longitudinal incision over the sternum, and. 



