THE BLOW-FLY. 157 



All blow-flies can becoine the authors of epidemics. Dr. 

 Maddoxread a paper before the Royal Microscopical Society, 

 in which he detailed the results of experiments especially 

 about the relations between the common-fly and the comma 

 hacUlm. According to the Scientific American the results of 

 all his investigations lead him to believe that the cornnia 

 hac'dlm from cultures can pass in a living state through the 

 digestive tubes of some insects, and through this fact, that 

 such insects are likely to become an important means of dis- 

 tributing disease, especially to animals that feed upon them. 

 This is in accordance with the views of Dr. Grossi, that "in- 

 sects, especially flies, may be considered as veritable authors 

 of epidemics and agents in infectious maladies." 



As these flies deposit their eggs on open sores or upon 

 wet, filthy parts of the skin, serious trouble may be caused. 

 To prevent this all wet and filthy hair should be cut and the 

 w^ounds should be kept clean and rendered antiseptic. A 

 good lotion for this purpose is made by mixing one part of 

 carbolic acid with fifty parts of water; or a mixture should 

 be made of one ounceoilof tar and twenty ounces of sweet-oil. 



It is stated from tiiue to time that maggots have been 

 vomited from the human stomach. Such maggots are the 

 young of blow-flies or of other similar flies w^hich may have 

 been swallowed in some way, and as they can exist for some 

 time in the stomach and intestines they can cause serious 

 trouble. The mysterious fly-disease {Jfi/ias/'s) is caused by 

 the presence of such maggots in the interior of human beings. 



The maggots of Sarcophaga latifrons have repeatedly 

 been removed from ulcers in the ear, and other cases have 

 been reported where such maggots had destroyed vision by 

 penetrating to the eye. 



About the very worst of such flesh- or blo^v-flies is the 

 Texas screw-worm, an insect that has a very bad reputation, 

 and what is worse, one that is well-earned. As this insect is 

 also found in Minnesota, and has already done some harm, 

 it is best to describe it more in detail. 



