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 
