596 HORSE, SWINE AND POULTRY DISEASES 



deviations from health involve the integrity of this fundamental 

 principle, cleanliness, it necessarily follows that any attempt at 

 recovery must seek to restore cleanliness. As cleanliness is the first 

 law in the science of preserving health, so is it the primary prin- 

 ciple in the healing art. 



This fundamental doctrine of cleanliness as applied to the 

 well-being of poultry may be expressed in three general principles: 

 (1) Clean intake; (2) clean output; (3) clean surroundings. The 

 intake includes food, drink, and air. The output consists of ex- 

 crementitious matter from the alimentary tract, the excretion from 

 the kidneys, and the products of the reproductive system. The 

 surroundings comprise houses, grounds, and air. 



DEFINITION OF CLEANLINESS. 



What does the word cleanliness mean? If one studies the dic- 

 tionary, he will find that cleanliness means freedom from dirt or 

 foreign matter. One's conception of cleanliness must therefore 

 depend upon the notion of dirt, and that notion is largely a matter 

 of training, habits, and associations. 



The philosopher has defined dirt as "matter out of place." 

 Matter that is all right and clean in one place may be all wrong 

 and dirt in another. Moreover, cleanliness is one thing to the 

 ordinary person, but altogether another matter to the hygienist, 

 The eye with the microscope has a larger apprehension of dirt than 

 the unaided eye. The good housekeeper sees with annoyance the 

 specks of dust and is satisfied with their removal; the intelligent 

 surgeon whose vision has been enlarged by the microscope sees the 

 millions of bacteria that use a single speck of dust as an airship, 

 and he knows of the possibility that tetanus bacilli or other germs 

 may fall, unseen, from such dust on to the raw surface of an ex- 

 posed cut upon a person's skin. He therefore can not call the cut 

 surface of the wound "clean" until he has thoroughly washed it 

 and applied disinfectant in order to kill those germs. The apples 

 on the street vender's stand glow with apparent cleanliness, but 

 those same apples may have been polished with a soiled pocket 

 handkerchief, and the bacteriologist might well tremble at the 

 thought of the tubercle bacilli that may be on those skins. The 

 cook washes the lettuce leaves to remove the bits of adherent dirt, 

 and the salad made therefrom may look and taste all right; but 

 the unaided eye can not see the typhoid germs or other intestinal 

 microbes derived from the sewage with which that portion of the 

 garden stuff was fertilized. 



The conception of dirt and cleanliness under discussion is 

 formed by the sanitarian's training, habits, and associations. 

 Farmers and poulterers are a class who read, and therefore have be- 

 come somewhat familiar with the horizon of the scientist, so as to 

 appreciate, in air and soil, in food and drink, in houses and incu- 

 bators, upon the external and internal coverings of the chicken's 

 body, the presence of innumerable microbes, many of them cap- 

 able of producing decomposition and putrefaction, and thus likely 

 to cause sickness through absorption of their poisonous products; 



