There are, consequently, two factors in the production of southern fever: first, the tick; and secondly, the protozoal microorganism which lives in and destroys the red blood corpuscles of the affected cattle. Where the tick obtains the protozoön is not yet known, but that the microorganism can be transmitted from one generation of ticks to another through the egg is demonstrated. It is important to learn through how many generations of ticks the germ can be transmitted without losing its virulence and whether there is any other means by which it gains access to the system of cattle in addition to being introduced by the punctures made by ticks.

There are evidently ticks which do not harbor this minute parasite, because cattle susceptible to southern fever are frequently badly infested with ticks without showing any marked symptoms of disturbed health. On the other hand there may be means by which the protozoon gains access to the blood of cattle independently of the agency of ticks; but it appears from the investigations just made that in the great majority of cases cattle are infected by means of ticks. That is, the adult ticks drop from southern cattle and lay their eggs upon the pastures. The eggs hatch and the young ticks get upon susceptible cattle and produce the disease.

If this supposition is correct it is of great practical importance. In the first place, susceptible cattle taken to the South for breeding purposes could be protected from the fever by keeping them in such a manner that they would not become infested by ticks. That is, they could be kept in stables not previously occupied by other cattle, bedded with clean straw and fed upon hay or grass cut from fields where no cattle had been for a considerable time. In the second place, it would seem that southern cattle might be rendered innocuous by washing them with some preparation that would destroy the ticks, or by holding them upon uninfected ground a sufficient time for the ticks which are upon them to mature and drop to the ground, but not long enough upon any one pasture for the young ticks to hatch and reinfect them."

The probability of reaching important practical results is such that these investigations should be continued until the subject is thoroughly understood.

SWINE DISEASES.

The investigations of swine diseases have been carried on with the idea of determining (1) the relative prevalence of hog cholera and swine plague, (2) the value of protective inoculation by various processes as a preventive of hog cholera, and (3) to test the practicability of preventing those diseases by the use of the ptomaines or bacterial products developed by growing the germs in proper culture

media.

These researches have shown that swine plague is relatively more prevalent than was first anticipated and that it is probably the cause of as much mortality as is hog cholera. They also confirm our conclusion of last year, that inoculation is not a practical or reliable method of preventing hog cholera.

The investigations of the bacterial products have been very interesting, at least from a scientific point of view and as regards their application to the prevention of human diseases. This interest is increased at the present time by the announcement of the celebrated German investigator, Professor Koch, that he has discovered a remedy for tuberculosis. This remedy is now believed to be a product H. Mis. 270———6

of the growth of the bacillus of tuberculosis in appropriate culture material.

It should not be forgotten that the possibility of applying these bacterial products to the prevention and cure of diseases was first made evident by the investigations of the Bureau of Animal Industry, and that if Professor Koch's remedy is of the nature supposed his method consists in the application of a principle discovered here.

Our recent work in this line has been to separate the substance which has this preventive power from the many other chemical principles present in the culture liquids, and to study its nature and properties. This chemical work was placed in the hands of Dr. von Schweinitz with general directions as to the character of the investigations, in the spring of 1890, and since that time the products of the hog-cholera germ have been studied quite thoroughly and their remarkable power in conferring immunity has been confirmed.

Unfortunately these products are very irritating, and in the dose necessary to produce an effect upon the system of the hog they cause an inflammation at the point where injected into the tissues, which is a great objection to their use. They could be given in smaller and more numerous doses, but this increases the expense so much as to make their use impracticable. When administered by way of the stomach their effect is lost.

That this method of preventing disease with other maladies and other species of animals and particularly with mankind is destined to be of much service seems very probable. With this ultimate object in view we have endeavored to produce artificially a drug which would have the same composition and effect as the bacterial products. By such a process we hope to obtain the preventive agent at less expense and without danger of being contaminated with the deadly germs that cause the disease. To a great extent these researches have been successful and we are now able to produce a substance entirely by chemical processes which not only resembles the bacterial product of the hog-cholera germ in composition but which has almost if not quite the same power of conferring immunity from the disease.

By these preliminary studies we have worked out the proper methods of investigation, and it is hoped that by applying them to tuberculosis and other diseases which affect animals of greater value than hogs successful means of prevention may be secured. And if incidentally these methods of prevention can be applied to diseases affecting mankind, their value to the country and to the world will only be increased thereby.

GLANDERS.

The improvement in the District of Columbia in regard to this disease is shown by the number of affected animals discovered in 1890 as compared with those in 1889. The last report of this Bureau gave the number of horses condemned each month up to and including November, 1889. Since then the number condemned monthly has been as follows:

During the twelve preceding months the number condemned was seventy-eight. During the spring of 1890 a very general inspection was made through the city with especial attention to all large stables, and the fact that so few animals were discovered shows that now the District is very nearly free from the disease. It is impossible, of course, to maintain absolute freedom from such a malady, as it is frequently introduced by horses from other parts of the country that are sold in this market.

PUBLICATIONS.

The great need of publications for gratuitous distribution which treat in a systematic and thorough manner of the different subjects connected with the breeding and care of the domestic animals has long been apparent. The field is a large one to cover and can not be properly treated in the works of private firms without making the publications so expensive that they would be beyond the reach of the people who most need them. For this reason the Bureau of Animal Industry has undertaken the preparation of a series of reports on the breeding and management of live stock in health and disease.

These reports are intended for popular use, and while so complete and accurate that they will be useful to the professional man or scientist, their language is to be as plain and free from technicalities and unusual expressions as is consistent with a clear and forcible treatment of the subject. Their purpose is educational, and it is hoped that they will do much to clear away the absurd traditions and practices born of ignorance which still obtain in some parts of the country, and that they will furnish a basis for a progressive and successful management.

Large amounts of money are being expended for improved stock, and unless buyers understand the peculiar characters of the different breeds, the conditions under which they have been formed, the care which is necessary for their existence, and the diseases to which they are subject, they can only meet with indifferent success in breeding them. The best stock is the result of the most intelligent management, care, and selection, and unless this management and selection are continued the stock will deteriorate.

This

The number of breeders who have succeeded in establishing or improving a breed have been relatively few, and the number who can even maintain all the good qualities of our most improved breeds without continually infusing new blood are not numerous. shows a lack of knowledge among the great majority of breeders as to the requirements of improved breeds of animals which calls for correction. It is the object of this Bureau to collect this valuable. information from the few who do know and distribute it broadcast to the many who ought to know.

The first work of the series treats of the animal parasites of sheep, one of the most important subjects which confronts the sheep breed

This work has been received with great favor, and the first edition was exhausted within a few months after it was ready for distribution. A second edition was immediately ordered and the applications for copies are still numerous.

The second report of the series is at this writing going through the press, and it will probably be ready for distribution by the 1st of February, 1891. It treats of the diseases and accidents from which

horses suffer, and it will be useful to an even larger class than the volume which has preceded it. No labor has been spared either on the text or the illustrations, and we have endeavored to make it compare favorably with the splendid volumes in other and less practical fields of science and research which the various departments of the Government have from time to time issued.

A volume on sheep husbandry and one on trotting and thoroughbred horses will be ready for the press almost as soon as the report just mentioned is out of the way. In addition to these the regular report of the Bureau of Animal Industry for the years 1889 and 1890 is in an advanced stage of preparation and will be sent to the press early in 1891.

CONDITIONS AFFECTING THE PRICE OF HOGS.

The conditions affecting the price of the animals produced upon the farm is one of the most interesting and important studies which can be made for the benefit of the stock grower, and as the chief of the Bureau has recently made an investigation of this subject a brief statement of the facts and conclusions are inserted in this report.

The fluctuations in the price of hogs appear at present to be more easily traced and more subject to principles that can be definitely formulated than the variations in the price of other farm animals, and consequently they have been selected for this preliminary investigation.

The calculations which follow are principally based upon the statistics of the United States Census Bureau, the estimates of the Statistical Division of the Department of Agriculture, the report of the Bureau of Statistics of the Treasury Department, and the annual report of the Cincinnati Price Current. The population for the intermediate years is estimated by the rate of growth for the ten years, taking account each year of the immigration.

The following table shows the population of the United States, the total hog product including lard put on the market by the packing establishments, the quantity which this constitutes per capita of population, the quantity of hog product exported, and the total and per capita quantity remaining for home consumption for each year since 1873:

The quantity of pork products put upon the markets by the packing houses of the East and West is partly estimated, but is so nearly correct that the exact figures could not in any way change the conclusions which are here drawn from the table.

We see by this table the enormous amount of hog product put upon the market in this country, an amount which varies in round numbers from 1,457 million pounds in 1876 to 3,047 million pounds in 1890. No account is taken of .the hogs killed and consumed by farmers or sold in villages, towns, and cities, but which are not packed, as there are no definite data from which it can be determined. Although this quantity is large it probably has no great effect upon the price of hogs in the packing centers, since it is the visible supply of hog products, the quantity put into the channels of commerce by the packing establishments, which we would expect to influence prices.

As would be expected there has been a great increase of hog product during the years covered by the table. From 1873 to 1877 the total amount was less than 2,000 million pounds per annum, varying from 1,457 millions in 1876 to 1.701 millions in 1874. From 1878 to 1889 the product was over 2,000 millions each year, varying from 2,045 millions in 1878 to 2,677 millions in 1887, and reaching the enormous aggregate of 3,047 millions in 1890. The quantity which this constitutes per capita of population varies from 32.1 pounds in 1876 to 51.7 pounds in 1879 and is only 48.7 pounds for the great output of 1890.

The quantity of pork products exported reached the highest figures in 1880 and 1881, dropping off in 1882 and subsequently, as a result of the unfavorable restrictions and prohibitions imposed by several foreign governments. Deducting the exports from the total production we find that the quantity left on the domestic market for home consumption has varied from 19.5 pounds in 1877 to 31.4 pounds in 1887 and was 30.1 pounds in 1890.

In order to bring out the effect of demand and supply upon the price the following table has been compiled, which shows in parallel columns the cost of the hogs used for the winter packing in the West, the total hog product per capita, and the domestic supply per capita for the year:

This table shows that in a general way the cost of hogs has varied inversely with the total hog product per capita, that is to say, the cost has increased in most cases as the product decreased, and vice The variations are not always, however, in this inverse sense,

versa.