Calliphoridae 425 



(Fig. 77) and incubated in a moist chamber in the fly cabinet. On the 

 following day the slide and the cloth with unhatched eggs and eggshells 

 are removed from the vial. When the larvae approach the size desired 

 by the surgeon microscopic examination and cultures are made of the 

 partially liquified maggot food and the vials are placed in the cool 

 cabinet at io° C. When bacteriological tests warrant it, the maggots 

 are ready for the surgeon. If not needed at once, they may remain in 

 the cool cabinet for a week or more before they are implanted. 



Disinfection with Formaldehyde. After decanting the 2% hydroxide 

 from the separated eggs they are washed by pouring on 0.02% formic 

 acid, decanting and repeating the washing until the egg suspension is 

 neutralized as indicated by phenolphthalein. The eggs are then im- 

 mersed in 6.25% formalin and allowed to remain for 20 minutes at room 

 temperature. They are strained, washed with water, transferred to 

 larval vials, incubated, and the maggots are tested for sterility. 



Disinfection with Mercuric Chloride. After the hydroxide is de- 

 canted from the separated eggs they are washed with 0.02% hydro- 

 chloric acid, and immersed in the mercuric chloride solution at room 

 temperature for 15 minutes. The technique used after formaldehyde 

 disinfection is then followed. 



Disinfection with Sodium Hydroxide Followed by Other Disinfect- 

 ants. The efficiency of sodium hydroxide is less generally known than 

 that of some other disinfectants. Therefore further to assure sterility of 

 the clinical maggots the eggs may be treated with another disinfectant 

 following the hydroxide. If formaldehyde or mercuric chloride is chosen, 

 the eggs are first disinfected with $ r 'c sodium hydroxide. They are then 

 washed and treated with either of these disinfectants as is done when it 

 is used alone, with the exception that the immersion in the disinfectant is 

 for 10 minutes. 



STERILITY OF CLINICAL MAGGOTS 



The chief danger in the maggot treatment lies in the possibility that 

 disease producing agents might be introduced into the wound with the 

 maggots. In routine rearing of maggots no laboratory method is avail- 

 able by which absolute sterility may be determined. This limitation 

 makes it imperative that every reasonable precaution be taken which 

 will tend to insure sterility. 



Sterility is judged from the technique used in producing the maggots 

 rather than from tests made afterwards. Tests are made, however, of 

 all vials of maggots used. Each worker should choose for himself those 

 tests which he deems sufficient. Microscopic examination of partially 

 liquified food and inoculation of glucose bouillion and deep glucose agar 

 with it are probably sufficient for routine rearing in most instances. 



