The Microscope. 109 



feature. Inigate with dilute acetic acid : nuclei appear beneath 

 the sarcolemma. Prepare a little strip of heart muscle. Observe 

 the striations and the short, branchate appearance of the fibers. 

 Take little pieces, the size of pin's head, from liver and spleen ; 

 tease in glycerin and examine. 



(Note. — As glycerin renders a specimen more transparent, it is 

 to be preferred to the salt solution when the object to be teased is 

 very opaque. If the glycerin be found to be too ropy, so that it 

 interferes with the teasing, distilled water can be added to suffi- 

 ciently thin it.) 



This constitutes the lesson. Do not stop with the tissues 

 mentioned above, but tease small pieces of everything that can be 

 subjected to the operation. Study the results carefully, and it will 

 not be long before beauties will be recognized in a teased mount 

 equal to any to be found in the most elaborate sections. 



Hints. — For cleaning new slides and cover-glasses, it will be 

 sufficient to polish them with a piece of soft, old linen. If they still 

 seem cloudy, dip them in alcohol and rub briskly. If they have 

 been used with glycerine or salt solution they should bo washed 

 with soap and hot water before polishing. 



It requires considerable dexterity to quickly cleanse cover- 

 glasses without breaking them. With a linen rag take them always 

 on the flat between fore-finger and thumb, and nib gently to and 

 fro. About a dozen will be destroyed before comparative success is 

 attained. To many who find the linen too clumsy for cleansing 

 these fragile glasses, we can recommend the so-called Japanese filter 

 paper, much used by dentists in their work. Prof. Gage, of Cornell, 

 uses it for cleansing the lenses of objectives and oculars. (See 

 MiCKOscoPE for December.) It is veiy soft and bibulous, and so 

 thin as to allow very delicate manipulation. 



In all work remember that " Cleanliness is akin to godliness." 

 In spite of one's best endeavoi", however, some dirt will be found in 

 all specimens. It will be necessary, therefore, that the microscopist 

 should be familiar with its most common forms when seen under the 

 microscope. A good method for studying dirt is to leave a slide 

 exposed till covered with dust. On this place a drop of water or 

 o-lycerine, and cover. Examine in water the fuzz from a blotting 

 pad and little fibrils from different cloths. 



The recognition of air bubbles is also important. With a 

 needle agitate a drop of glycerin placed on a slide. Slap the cover 

 on it and examine the bubbles of different sizes. Focus up, and the 



