HABITS OF THE ADULT FLY 45 



brief discussion of the mouth parts of the adult fly, its 

 food must be liquid, and when it alights upon a solid 

 a plentiful flow of a salivary liquid enables it to make 

 some slight impression and to gain sustenance. Thus it 

 drinks as well as eats, and liquids apparently contain- 

 ing little that will help it to exist are sought by it, but 

 it especially prefers semi-liquid mixtures. Every one 

 who reads this book knows how in the old days, and 

 even now in some places, the typhoid fly swarmed or 

 swarms in a certain class of public restaurants and in 

 poorly cared-for eating places. The story of the man 

 who entered a dimly lighted railway restaurant and 

 asked for "a piece of that huckleberry pie" and was in- 

 formed that it was not huckleberry but custard, is lit- 

 erally true. Dr. Theobald Smith phrased it very hap- 

 pily in a paper written a few years ago in the following 

 words : "When we go into a public restaurant in mid- 

 summer, we are compelled to fight for our food with 

 the myriads of house flies which we find there alert, 

 persistent and invincible." Doctor Smith has been very 

 fortunate in the choice of the word "persistent." The 

 typhoid fly does not seem to have any common sense. 

 At one time he is alert, to use Doctor Smith's word, 

 and it is impossible to catch him, but his persistence 

 even in the face of imminent danger is one of his char- 

 acteristics which is most impressive. When one lies 

 drowsily in bed of a summer morning with but one fly 

 in the room, "persistence" is the only word to apply 

 to its annoying return again and again and again to 

 the face of the sleeper in spite of repeated slaps. Here 



