452 



APPENDIX 



Mites, Fleas and Various Small Insects. By simply taking i or 2 drops of 

 liquid petrolatum and mounting the specimen in it then covering with a cover- 

 glass one is able to study the details of these objects almost as well as if they were 

 passed through acetone and xylol into balsam. Liquid petrolatum is also most 

 excellent for mounting the aerial hyphae of fungi with their sporangia as well as for 

 Romanowsky stained blood smears. 



Pathological Specimens. Pathological tissues which are to be sent to a labora- 

 tory for sectioning or to be kept for future study should be fixed by one of the 

 methods given in Section A of the appendix. 



Formalin fixation is the more convenient that with Zenker's fluid the more 

 perfect. After fixation with Zenker's fluid the pieces of tissue must be washed in 

 running water over night. 



After fixation the pieces of tissue are transferred to 70% alcohol in which they ma) 

 be kept indefinitely. 



For preservation of gross specimens the method of KAISERLING is generally use< 



Fix for from one to five days in Solution i. 



Solution I 



Formaldehyde, 200 c.c. 



Water, 1000 c.c. 



Nitrate of potassium, 15 grams. 



Acetate of potassium, 30 grams. 



The position of the specimen should be changed from day to day. There must 

 be at least five times as much fluid as specimen. Drain and transfer to 80% alcohol 

 for a few hours, then into 95% alcohol until the natural color is just restored. 



Finally preserve in 



Acetate of potassium, 200 grams. 



Glycerine, 400 c.c. 



Water, 2000 c.c. 



It is advisable to keep these specimens in the dark as light destroys the natui 

 color. 



To Prepare Flies or Mosquitoes for Transmission through the Mails. Wrap 

 the insect carefully in a piece of tissue paper (toilet-paper answers). Impregnate 

 sawdust with 5% carbolic acid solution and fill around the tissue paper in the box 

 containing them. (Barely moisten.) 



It is very satisfactory to take a tube form vial with a cork from the inner sur- 

 face of which two small shallow holes have been bored, one containing parafor- 

 maldehyd, the other camphor. The insect is mounted upon a pin stuck in the 

 cork, which latter is inserted and paraffined externally. 



C PREPARATION OF NORMAL SOLUTIONS 





A normal solution is one which contains the hydrogen equivalent of an element, 

 expressed in grams, dissolved in sufficient distilled water to make 1000 c.c. 

 hydrogen equivalent is the atomic weight of any element divided by its valence. Ii 

 a base, salt or acid, we use the molecular weight in grams divided by valence. 



