APPENDIX 379 



add 95 c.c. of 85% alcohol and filter while hot. Neutralize with ammonia until 

 precipitate begins to form. Then filter cold. 



i. Stain parasites taken from 70% alcohol for five to twenty minutes. 2. Dif- 

 ferentiate in 3% hydrochloric acid. 3. Pass through alcohols to xylol and mount in 

 balsam. 



Mites, Fleas and Various Small Insects. By simply taking one or two 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 hyphas of fungi with their sporangia as well as for 

 Romanowsky stained blood smears. 



Pathological tissues which are to be sent to a laboratory 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 may 

 be kept indefinitely. 



For preservation of gross specimens the method KAISERLING is generally used. 



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 natural 

 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 parafined externally. 



