120 APPENDIX. 



By the practice of dissection such a knowledge is gained 

 of the varied forms and internal organization of minute 

 creatures as can be obtained in no other way. 



There are doubtless many who, possessing a small Micro- 

 gcope, are unable by reason of their limited means to expend 

 money in the purchase of ready-prepared specimens. To 

 such, a few plain directions, if followed, will be of service, 

 and will enaole them to prepare their own. 



The materials necessary for the beginner are few, and not 

 expensive. In fact, the fewer the better ; for a multiplicity 

 is apt only to cause confusion. The following will be found 

 sufficient for all ordinary purposes, and may be obtained at 

 any optician's. 



Bottle of new Canada balsam. 



Bottle of gold- size. 



Bottle of Brunswick black. 



Spirits of turpentine small quantity. 



Spirits of wine small quantity. 



Solution of caustic potash (liquor potassce). 



Ether a small bottle. 



Empty pomatum-pots, with covers, for holding objects 

 while in pickle. 



Half a dozen needles mounted in handles of camel-hair 

 brushes. 



Pair of brass forceps. 



Two small scalpels. 



Pair of fine-pointed scissors. 



Camel-hair pencils half a dozen. 



Slips of plate-glass, one inch by three inches two dozen. 



Thin glass covers, cut into squares and circles half an 

 ounce. 



We will suppose that the beginner, having purchased the 

 necessary materials, is about to make his first attempt. Let 

 him attend to the following advice, and he will escape many 

 failures. 



He must bring to his work a mind cool and collected ; 

 hands clean and free from grease. Let him place everything 

 he may require close at hand, or within his reach. A stock 

 of clean slides and covers must always be ready for use. He 

 must keep his needles, scissors, and scalpels scrupulously 

 clean. An ingenious youth will readily construct for himself 

 a box to contain all his tools. Cleanliness is so essential to 

 success, that too much stress cannot be laid upon it. All 

 fluids should be filtered and kept in well-corked phials. A 

 bell-glass, which may be purchased for a few pence, will be 

 found exceedingly useful in covering an object when any delay 



