no doubt that the markets of Great Britain would at present take more cattle than are being sent.

The greatest hindrance to the export trade in live cattle is the regu lation of the British Government requiring that all American cattle shall be slaughtered on the docks within a period of ten days after they are landed. This prevents the owner from holding them until they can recover from the effects of the voyage and until the market is in the best condition for selling. Canadian cattle, which are allowed to enter England without any restrictions, are said to yield the shipper from $10 to $15 per head more than can be realized from steers shipped from the United States. The effect of this difference. in returns is very marked, both upon our trade and upon the market value of cattle in the United States. If our shippers were able to secure $10 or$15 per head more for their animals it would of course stimulate the trade, and they would be able to pay nearly that a mount more for steers purchased in this country. Such an advance in the price of export cattle would have a strong tendency to increase the price of all other kinds of stock. In this respect, then, the removal of the restrictions would be of the very greatest advantage to American cattle-raisers.

The removal of the English restrictions would also enable our shippers to send a kind of cattle which now can not be exported at all to Great Britain. There is no doubt but that our thin steers, or feeders as they are called, could be supplied to the English farmers. for feeding purposes much cheaper than store cattle are now obtained from Ireland. The vast numbers of this class of steers which have been thrown upon the markets of the United States during the last three or four years have so exceeded the demand that prices have declined below the cost of production. The inevitable tendency is to force down the price of all meat-producing animals. If the foreign trade would take a considerable number of these thin steers it would be of the greatest benefit in sustaining the prices in this country. The English farmers are already agitating this question and are looking to the United States as a possible source of supply. The prices of Irish store cattle have been so high, and the danger of these animals being infected with pleuro-pneumonia is such that there is no doubt that it would be of great advantage to the feeders of both England and Scotland if they could obtain the cheap and healthy steers which are found in such numbers in all the American markets. The number of this class of cattle which the English market could take is very uncertain. It has been suggested abroad that four or five thousand store cattle per day might be shipped from here. It does not appear probable that anything like this number could be sold to Great Britain for any considerable time. During the last five years the largest number of store cattle for feeding and breeding purposes sent from Ireland to England and Scotland in any one year is 405,540, or about 1,100 per day. This would indicate that from 100,000 to 150,000 store cattle per year would be as much as we could expect to send, if the restrictions were removed and the facilities provided for shipping that many animals in addition to the regular trade in fat cattle. Even this number would greatly relieve our markets and tend to restore prices to a point which would remunerate our farmers for the cost of production.

It has been suggested that Ireland would probably take a large number of our heifer stock for increasing their breeding herds. It is also possible that our store cattle might be sent to Ireland for fat

tening. What the effect of this would ultimately be on our trade in fat cattle can not easily be predicted, but for a time at least it would not be great, because the store cattle shipped to Great Britain and Ireland would simply replace cattle which under other circumstances they would raise. It would, however, enable them within a few years to put more beef steers upon the home market, and in that way tend to lessen the number of fat cattle which would be taken from abroad. This need not cause any anxiety, because before such a result could be reached the over-production of cattle in this country would be a thing of the past. There can be but little doubt that within the next four or five years the population of the United States will have so increased beyond the development of the cattle industry that there will no longer be the same necessity of a large export trade.

It has been urged as an objection to exporting store cattle that it would be better for our farmers to feed them at home and ship them in a fat condition. This objection is rather theoretical than practical, and should at the present have little weight. As a matter of fact large numbers of store cattle are thrown upon our markets and depress prices, and, instead of being purchased for feeding, are killed and used for canning purposes. To send a part of these abroad would relieve the market and would not in the least lessen the number of steers that would be fed in this country. Undoubtedly it would be a better agricultural operation to feed such cattle at home and sell them fat than to sell them as store cattle, but as long as prices are so low that feeding is unprofitable they would be thrown upon the market, and it is just as well for them to go abroad as to be killed and canned in this country. The only question to be decided is, in what way would the American farmer obtain the best price for his stock. If the restrictions were removed there is no doubt that a better price could be obtained by exporting store cattle than to kill them here for canning.

The other markets of Europe are being closed against live cattle. An experimental shipment sent to Germany during the past summer realized excellent prices, and undoubtedly a large trade would have resulted were it not for the prohibitory restrictions which were at once enforced.

As has been shown above, the price of cattle in this country is greatly influenced by the price of pork. For this reason any increase of our exports in pork products would have a tendency not only to increase the price of pork in this country, but it would undoubtedly react upon the cattle trade and improve the price of beef as well. For this reason it is particularly important that efforts should be continued to secure the revocation of the prohibitory restrictions placed by various European nations upon our pork products.

There is little doubt that the markets of Europe would take all the surplus animals and meat products of the United States if these markets were not partially or entirely closed by arbitrary restrictions. Our breeding stock has now been improved until our animals compare favorably with those of any other country. They are raised under the most healthful conditions, and their price is far below that of animals of equal quality which can be obtained in any part of the world. There is, consequently, every reason why the people of Europe, where meat is so high in price as to be a luxury rather than a staple article of food with the masses, should look to this country to supply their needs.

INVESTIGATIONS OF INFECTIOUS ANIMAL DISEASES.

The account of the investigations of swine diseases which follows is interesting for several reasons. In the first place it demonstrates what, indeed, might have been expected, that both hog cholera and swine plague may exist under different forms. These differences are due to the fact that the germs which produce the outbreaks are of very different degrees of virulence. An important point is that the changes found in the internal organs on post-mortem examination differ materially in the same disease according to the virulence of the germ which is the exciting cause. It is therefore probable that there will be found all shades of difference in these diseases connecting the types first described in the reports of this bureau with the very distinct types described on these pages.

These extreme differences in the type of disease which may be encountered undoubtedly explain the variety of results of preventive and curative measures in the hands of different individuals. It also explains why hog cholera has shown the most actively contagious characters in some outbreaks while in others it only spreads slowly or not at all.

These researches also confirm the conclusions reached in the studies made during 1886, 1887, and 1888 as to the existence of the two dis tinct communicable diseases of swine which we have called hog cholera and swine plague. In some cases the germs of both diseases were found in the body of the same animal, indicating that death resulted from a complication of the two maladies. In other instances the most elaborate researches would only reveal the presence of the swine-plague germ, while at still other times only the hog cholera germ could be found. We have here further proof, therefore, that both of these germs are fatal, and that they may act each by itself in producing disease, or the two may be present at the same time and each develop its peculiar effects in the body of the same animal.

The following brief account of the investigations conducted under my direction into the nature of infectious animal diseases has been prepared by Dr. Theobald Smith, who is in charge of this branch of the work of the Bureau of Animal Industry. It will be found of great interest to all who desire a more thorough knowledge of these maladies. Only the most important results are outlined, all minor details of experiments and the autopsy notes being reserved for special reports of the Bureau of Animal Industry.

ON TWO OUTBREAKS OF MODIFIED HOG CHOLERA.

I. Early in January a disease broke out in a small herd of swine near Knowles, Md., which, upon examination, proved to be a modified form of hog cholera. Considerable attention was paid to this outbreak, and the bacillus causing it was carefully studied and identified as a variety of the hog-cholera bacillus described in the reports of 1885-'88, and in the special report on hog cholera. The importance of thoroughly determining the various forms of swine disease, in view of prevention and extermination, and of the methods to be employed for this object, need not be insisted on at this time. The importance is a sufficient reason for these investigations, which can here be given only in abstract.

General characters of the disease.-On December 15, 1888, Mr. P. had eight fine shoats, about three months old, and on this day he

purchased a cheap lot of pigs in the Washington markets. One of these died on the way home; two others died during the two following days, and within ten days seven had died. The last one of the new lot died, greatly emaciated, January 20, after a sickness of from three to four weeks. The original lot on the farm became infected early in January, and up to January 22 four had died. Of the remaining four, two were quite sick and two apparently well. Among the symptoms noticed by the owner was a rapid falling away in flesh, while the appetite remained fairly good up to the time of death. There was a severe cough, coupled with a nasal discharge and considerable diarrhea. In the later stages of the disease the skin of the limbs, belly, and ears became deeply reddened. The ears turned almost black, and "lopped like the ears of a dog." On the limbs and belly the skin became "scabby like a person with small-pox."

One of these pigs was examined on the farm; two others in which disease was manifest were taken to the experiment station of the Bureau, there placed in clean, disinfected pens with board floors, and fresh pigs put with them to determine whether the disease was communicable or not. The following table shows that the disease could be communicated from one animal to another without the intervention of the soil. It also gives the time elapsing between the - exposure and the death of the animal exposed:

A few pigs placed in the pen with these did not take the disease; a few died rather prematurely on account of injuries received by fighting with one another. The four cases recorded in the table (Nos. 121, 126, 128, 116) are sufficient to establish the fact that a period of from three to four weeks is sufficient from the first day of exposure to destroy the animal. It should be borne in mind that this period holds only for pigs constantly exposed to virus in a small pen.

Lesions produced by the disease.-Unfortunately this outbreak, like so many studied since 1886, was a mixture of two diseases. We may now, after the investigations of the past few years, lay down the general statement that almost all extensive lung disease is caused by the swine plague germ. At the same time it is difficult to determine with any degree of certainty, when the outbreak is of a mixed character, the exact rôle which each germ plays in causing disease of the stomach and intestines. The hog-cholera germ may cause certain injuries to the mucous membrane, and the swine-plague germ coughed up from the air-tubes and swallowed may cause additional injury to the whole digestive tract. It is also impossible to determine definitely which germ enters the body of the pig first. Either may prepare the way for the other. As there is much variation in the activity or virulence of either germ, it is very probable that the most virulent makes the first attack and thereby paves the way for the other. We may likewise assume that the germs are transmitted together from one herd or pig to another.

In the pigs obtained from the farms (Nos. 1, 2, 3) as well as in some of the exposed, the lungs, stomach, and large intestines were diseased. The lung disease was a more or less extensive broncho-pneumonia or catarrhal pneumonia, involving also the larger air tubes. The solidified lung tissue was nodular to the touch, the nodules being caseous masses in the ultimate bronchioles and air-cells. The filling up of these spaces with cellular elements had gone on to such a degree that there was distinct saccular dilation of the small air-tubes (bronchiectasis). With this lung disease the swine-plague germ was always associated.

The stomach was either deeply reddened, hyperæmic in the fundus, or else there was (outside of the fundus) a peculiar diphtheretic inflammation, accompanied by cellular exudation, necrosis of the mucous membrane, and subsequent ulceration. This lesion had not previously been observed in swine disease, excepting in a few pigs which had been fed with cultures of hog cholera bacilli. The hyperæmia of fundus and diphtheretic condition of the remainder of the mucosa were in a few cases found associated together.

The lesions of the large intestine were quite varied in character. In several cases they consisted of large neoplastic projections from the mucous membrane, often one-half inch high and one inch wide, The neoplasms were very firm, yellowish white, capped by a thin black slough and extended into the muscular coat, or even to the serosa. Some had the concentric markings quite common in hog cholera, while others were irregular in outline. The more common appearance presented in this outbreak by the large intestine was a complete necrosis of the mucosa over large areas. The mucosa itself was converted into a rather firm, yellowish-white, homogeneous layer, the surface of which was made irregular by small lumps of caseous matter reminding one of rough cork-lining. In some cases the sheet necrosis was more smooth. In a few instances the upper large intestine was beset with numerous small ulcers which seemed to have their origin in the solitary follicles and mucous glands.

How far the swine-plague germ contributed to the disease in the digestive tract it is of course impossible to say. Its presence was detected several times by inoculating rabbits from the mucous membrane. The investigation as a whole seems to indicate that its action was a subordinate one.

Characters of the hog-cholera bacillus causing this disease.-The methods employed in isolating the pathogenic organisms were in general the same as those hitherto employed. They consisted in. tube cultures usually agar and bouillon from the spleen, in plate and roll cultures (agar and gelatine), from the diseased lungs and pleura, and from the recently diseased mucosa in the stomach and large intestine. The cultures were re-inforced by the use of inoculations into rabbits from the same organs, as well as from cultures made directly from the pigs to test the disease-producing character of the bacteria thus obtained. The results from these different lines of work usually confirmed one another and may be briefly summarized. The hog-cholera bacilli were found in the spleen in the majority of the cases examined. In several cases plate cultures from the deeper layers of diphtheretic deposits and ulcers contained a large number of colonies of the same bacilli. The swine-plague bacteria were present in the diseased lungs and occasionally found in the digestive tract. The hog-cholera bacillus of this outbreak differed in a number of characters from the one found in outbreaks since 1885.