Some of my readers may take exception to me either in regard to roup or white diarrhoea. Roup is a disease of the wrong system and careless management. White diarrhoea, so-called, is a matter of wrong incubation. The high mortality of young chicks, though not an epidemic disease, shares with excessive cost of production, very much of the responsibility for poultry farm failures. At the present writing the poultry editors of the country are having much discussion over the conclusion of Dr. Morse of the Bureau of Animal Industry to the effect that white diarrhoea is caused by an intestinal parasite similar to the germ that causes human dysentery. Dr. Morse's opportunities for investigation have been somewhat limited and as the intestines of any animal are always swarming with various organisms, it will take very conclusive evidence to prove that the doctor is right. Practically the naming of the germs that attend the funeral is not particularly important for the reason that it has been thoroughly demonstrated that with good parentage, good incubation and good brooder conditions, white diarrhoea is unknown. The Causes of Poultry Diseases. Poultry ailments are assignable to one of the three following causes, or a combination of these: First, hereditary or inborn weakness; second, unfavorable conditions of food, surroundings, etc.; third, bacteria or animal parasites. A great many chickens die while yet within the shell, or during the growing process, there being no assignable reason save that of inherited weakness. To this class of troubles the only remedy is to breed from better stock. It is as much the trait of some birds to produce infertile eggs or chicks of low vitality as it is for others to produce vigorous offspring. The second class of ailments needs no discussion save that accorded it under the general discussions of the method of conducting the business. The third class of ailments includes the contagious diseases. It is now believed that most common diseases are caused by microscopic germs known as bacteria. These germs in some manner gain entrance to the body of an animal, and, growing within the tissues, give off poisonous substances known as toxins, which produce the symptoms of the disease. The ability to withstand disease germs varies with the particular animal and the kind of disease. As a general rule it may be stated that disease germs cannot live in the body of a perfectly vigorous and healthy animal. It is only when the vitality is at a low ebb, owing to unfavorable conditions or inherited weakness, that disease germs enter the body and produce disease.