424 Phylum Arthropoda 



DISINFECTION OF EGGS 



In disinfecting eggs and rearing larvae for stock flies on autoclaved 

 food and maggots for surgical use, the following equipment is made 

 ready and autoclaved: Short 10 cc. shell vials; medicine droppers; 

 pipettes, 10 or 20 cc. capacity; Gooch strainers; rearing pans (Fig. 75) 

 and maggot rearing vials (Fig. 77) with food in them; 0.02% hydro- 

 chloric acid; 0.02% formic acid; and distilled water. A bit of alcoholic 

 solution of phenolphthalein is added to each of the acid solutions and 

 the water, and these are then distributed in large test tubes preferably 

 with lip and plugged. Bacteriological technique is used throughout. 



PRODUCING LARVAE FOR STOCK FLIES USING AUTOCLAVED 



FOOD 



Approximate 150 gm. of autoclaved lung and 50 gm. of autoclaved 

 liver are coarsely ground and placed within the inner container of the 

 larval pan. The one (Fig. 75, A) with a metal sleeve plugged with 

 cotton is preferred. Liquified agar, 1.5%, containing % to % of a hen's 

 egg, and % of a yeast cake or 1 gm. of dry yeast, is added nearly to 

 cover the meat. The lid is replaced, the metal tube inserted and the 

 whole autoclaved for a few minutes at 15 lbs. pressure and repeated the 

 following day. 



Eggs are removed with curved forceps and placed in a small shell vial 

 containing 2 % sodium hydroxide. They are readily separated by slight 

 agitation with a dropper pipette.* The hydroxide is decanted and a 5% 

 solution of it is poured on and allowed to remain for % hour or more at 

 room temperature. Approximately 700 eggs are pipetted to the gauze 

 of the Gooch strainef and washed by pouring or pipetting about 20 cc. 

 of 0.02% hydrochloric acid over them. The cloth with the eggs at- 

 tached is transferred with forceps to the inner surface of the metal 

 tube of the larvae rearing pan and incubated in the fly cabinet. On the 

 following day the metal tube with the cloth and unhatched eggs and egg- 

 shells are removed. 



REARING MAGGOTS FOR CLINICAL USE 



Eggs used for rearing clinical maggots are from flies obtained from 

 larvae grown on autoclaved food. Any one of the following methods 

 may be employed for disinfection of the eggs. 



Disinfection with Sodium Hydroxide. Eggs are disinfected, strained, 

 and washed as outlined above with the exception that they are allowed 

 to remain in the 5% hydroxide for i% hours at 32 ° C. They are trans- 

 ferred from the Gooch strainer to the slide in the larval rearing vials 



♦Simmons moistens eggs by means of a cloth wet with water and separates them me- 

 chanically. 



