The next fact in favor of the infectious character of a cold is that it begins with a chill, followed with a fever, runs a definite self-limited course, and, barring complications, gets well of itself in a certain time, just like the measles, scarlet fever, pneumonia, or any other frank infection. Colds are also followed by inflammations, or toxic attacks in other organs of the body, lungs, stomach, bowels, heart, kidneys, nerves, etc., just like diphtheria, scarlet fever, or typhoid, only, of course, of milder form and less frequently. Last, but not least practically convincing, colds may be traced from one victim to another, may "run through" households, schools, factories, may occur after attending church or theatre, may be checked by isolating the sufferers; and are now most effectually treated by the inhalation of non-poisonous germicidal or antiseptic vapors and sprays. One of my first experiences with this last method occurred in a most unexpected field. An old friend, a most interesting and intelligent German, was the proprietor of a wild-animal depot, importing foreign animals and birds and selling them to the zooelogical gardens and circuses. I used often to drop in there to see if he had anything new, and he would come up to see me, to tell me his troubles and keep my dissecting-table supplied with interestingly diseased dead beasts and birds. One day he came up in a state of great excitement, with a very dead and dilapidated parrot in his hand. "Choost look, Dogdor; here's one of dose measley new pollies I god in from Zingapore. De rest iss coffin' an' sneezin' to plow dere peaks off, an' all de utter caitches iss kitchen him." As parrots are worth from fifteen to thirty dollars apiece, "green" (not in color, but training), and he had fifty or sixty in the store, the situation was distinctly serious. Now, I was no specialist in the peculiar diseases of parrots, but something had to be done, and, with a boldness born of long practice, I drew my bow at a venture and let fly this suggestion:-- "Try formalin; it's pretty fierce on the eyes and nose, but it won't kill 'em; and, if you put a teaspoonful in the bottom of each cage, by the time it evaporates no germ that gets into that cage will live long enough to do any harm." Five days later back he came, red-eyed but triumphant. "Dogdor, dot vormaleen iss de pest shtuff I effer saw. It mos' shteenk me out of de shtore, an' de pollies nearly sneeze dere fedders off, but it shtopt de spret, an' _it's cureenall de seek ones_, an' I het a cold in de het, _an' it's curt me_."