The cereals are subject to many diseases which retard their development, rendering them unfit for food, and even poisonous. The relation of unwholesome foods to the diseases of the animal body are now being thoroughly studied, recent advances in chemistry and microscopy contributing valuable aid to the prosecution of such investigations. Some enthusiastic advocates of the germ theory of disease believe that many, if not all, the so-called disease germs may be transplanted into the human system with the food ingested. But whatever may be the real truth in regard to this subject, it has been positively demonstrated that many diseases of the human body may be produced by unwholesome food. The specific symptoms produced in man by the various grain diseases are not accurately known, consequently our remarks upon this subject must be of a very general character.

Pappenheim divides the diseases of the cereals into two classes, internal and external. The internal diseases are those depending upon conditions of soil, climate, cultivation, etc., and may be neglected in our discussion, as they produce no special disease of the body, only impairing the nutritive value of the grain.

The external diseases are of much greater importance, as they probably produce some of the most fatal maladies to which the human race is subject. These external diseases of the cereals are due to parasites, which may be either of an animal or vegetable nature. Among the animal parasites may be mentioned the weevil, vibrio tritici, which feeds upon the starch cells of the grain. Grain attacked by this parasite was at one time supposed to be injurious to health.

In 1844 the French Commission appointed to examine grain condemned a large quantity imported with this parasite, but afterward reconsidered their decision and permitted its sale, concluding that it was deficient in nutritive properties, but not otherwise unwholesome. Rust is the most common disease of the cereals, produced by vegetable parasites. Like the other diseases of this class, it is most prevalent in warm, damp seasons.

Prof. Hensboro is of the opinion that rust is but an earlier stage of mildew or blight, the one form of parasite being capable of development into the other, and the fructification characteristic of the two supposed genera having been evolved on one and the same individual.

Blight is a term loosely applied to a number of parasitic diseases. In it are included mildew, cories, and even rust and smut. The fungi producing these diseases attack the plant and seed at various stages of its growth. The whole kernel is affected, and not merely the external coat, as is sometimes maintained. When blighted grain is sown, the disease recurs the following year, often making it necessary to import new seed before the disease can be eradicated. Various remedies have been used to destroy the spores of these fungi, but all are uncertain and some are dangerous to health. Special machinery and methods have been employed in the mills to separate the mildew from the grain. Some of these succeed in removing the fungi and discoloration from the surface of the grain, but have no effects upon the parts within. Blighted grain is soft, and has an unpleasant taste and smell, and bread made of it is liable to be heavy and sodden.

It is undeniable that the use of blighted grain as food is exceeding dangerous to health. It is a well known fact that vegetable parasites may attack animals; the silk worm disease produced by the Botrytis baniana, being an example. It is stated that the same vegetable parasites which produce plant diseases, when transmitted to the animal body produce special affections, the form and appearance of the germs being altered by their environments. The same germs developed under different conditions of temperature and surrounding medium, assume forms so various that they have been supposed to belong to different species and even different genera. If there is any truth, then, in the germ theory of disease, it is not so very improbable that a fungus which will produce blight in grain may cause cholera or tetanoid fever in an animal.

Hallier, the famous physiological botanist, observed in 1867 that there was a peculiar disease of the rice plant associated with an epidemic of cholera. Rice plants fertilized with the discharges of cholera patients were affected with blight. A concentrated infusion of the blighted grain would produce changes in all animal substances, blood and albumen being converted into thin odorless products resembling in every respect the material found in the kidneys of cholera patients.

The most formidable of the diseases attributed to the use of diseased grain is cerebro-spinal meningitis, commonly known as spotted or blanoid fever. The disease is rare in England, but is frequently epidemic in the United States, in Ireland, and on the Continent. In 1873, in the State of Massachusetts alone, 747 persons died of it, and other epidemics even more fatal have lately occurred in New York and Michigan. The disease is a nervous fever attended with convulsions, the pathological lesion being congestion and inflammation of the membrane of the spinal cord and brain. Dr. Richardson in writing on the nature and causes of spotted fever concludes that it is due to the use of diseased vegetable substances, especially grain, and from a careful analysis of the statistics of this disease reported by the Michigan State Board of Health considers it demonstrated that "under favoring condition for its action diseased grain received as a food is the primary cause of the phenomena which characterize the disease." These views are substantiated by the experiments of Dr. H. Day, who found that by feeding rabbits on unsound grain, spasmodic affections were produced, due to inflammation of the membranes of the spinal cord and brain.

In warm climates, pellagra or Italian leprosy is said to be produced by eating diseased maize, which forms the principal article of food among the poorer classes of the rural districts. Pellagra is epidemic in northern Italy and the south of France. The disease is manifested by a redness and discoloration of the exposed parts of the body. It is most active during the hot weather, the inflammation subsiding in the winter, leaving a pigmentation of the skin. Each year the symptoms become more alarming, nervous disorders finally setting in, and a large number die insane. The disease is most prevalent in the country. In the towns, where maize is supplemented by other articles of food, it does not exist.

Ergot is a very common disease of the cereals. The fungus producing it was discovered in 1853, but for centuries previous its injurious effects upon the human body were recognized, and it was observed that ergot of rye was the most poisonous. Taken in large doses, ergot will produce nausea, vomiting, diarrhoea, headache, and weakness of the heart. In small repeated doses it will produce contraction of all the unstriped muscles, as those of the blood vessels, the womb, and intestines. Ergotium is the name given to the disease produced by the continued use of grain affected by this fungus. Aitken describes it as "a train of morbid symptoms produced by the slow and cumulative action of a specific poison peculiar to wheat and rye, which produces convulsions, gangrene of the extremities, and death. In countries where rye bread is much used ergotium is sometimes epidemic. This was a frequent calamity before the introduction of suitable purifiers into the mills. There are two varieties of the disease, the convulsive and the gangrenous. The convulsive form begins with tingling of the extremities, drowsiness, and headache, followed by pain in the joints, violent muscular contractions, and death.

The gangrenous variety begins with coldness and weakness of the extremities followed by gangrene and sloughing. This form is somewhat more fatal than the convulsive, the mortality of those affected being about 90 per cent.

Mouldy grain and bread have also caused poisoning. Prof. Varnell states that "six horses died in three days from eating mouldy oats. There was a large amount of matted mycelium, and this when given to other horses for experiment, killed them within thirty-six hours." The writer has himself seen seven hogs die within a few days while being fed on mouldy corn. Flour which has become stale may produce similar injurious effects, although most of the germs are destroyed in the process of baking. It is quite probable, however, that a poisonous substance is generated by the mould fungus, which cannot be destroyed in this way.--Milling World.