fore death. The destruction of red globules causing this condition could be easily demonstrated by examining blood taken from an incision through the skin. In severe cases, on the day before death, the number of red globules had fallen to about one million in a cubic millimeter of blood, the normal being about five and a half million. In one case, now recovered, the corpuscles were reduced in number nearly one-half several days before the temperature fell to normal, and a week later the number had not yet risen to three million. This enormous loss of red globules gave the blood an exceedingly thin, watery appearance. At the autopsy, besides the condition of the blood as noted, it was found to coagulate rapidly and form clots of unusual firmness.

The following description of the most obvious lesions will apply with more or less emphasis to all ten cases. The spleen is enlarged to several times its natural size. When incised, the tense capsule retracts and discloses a dark red, more or less disorganized pulp, occasionally running out as a semi-liquid mass. This engorgement is due chiefly to the presence of an enormous number of red globules. The liver is the seat of considerable disturbance. Its color is a yellowish brown. The parenchyma is deeply bile-stained, and when examined under the microscope the finest bile canaliculi are found plugged in many cases with consistent, cylindrical masses of bile. We have, in fact, a complete pathological injection of the intra-lobular biliary system. The bile in the gall-bladder is usually so thick that it scarcely flows. This is due to the presence of a large amount of solids in the form of minute yellow flakes. The kidneys in some cases are suffused with the color of hæmoglobin, and the connective tissue around them distended with reddish serum. Lesions of the fourth stomach were either absent or else did not differ in degree from those observed in healthy cattle. In one case there were superficial ulcers in the fourth stomach. A more or less extensive ecchymosis of the duodenum is occasionally met with, more rarely in the cæcum. In none of the eleven cases was there any appreciable jaundice. The condition of those organs engaged in the destruction of red corpuscles, such as the liver and spleen, as well as the large quantity of blood pigment in the urine, led to the inference that the disease was primarily due to an enormous destruction of red corpuscles. Moreover, the absence of bacteria pointed to parasites in the blood different from these organisms.

When the investigations of the past summer were begun particular attention was paid to the blood. This led at once to the discovery of peculiar bodies within the red corpuscles. In fresh spleen pulp they are visible as round or oval, nearly colorless, spots. from one-half to 2 micromillimeters (0 to 120 inch) in diameter on the disk of the red corpuscles, and always somewhat excentrically placed. Careful focusing leaves no doubt that they represent bodies within the corpuscles. There may be but one, quite commonly two. and very rarely three or four, in the same corpuscle. In organs kept in the cold for nearly two weeks they were still visible, but faintly, owing to the diffusion of the hemoglobin around and perhaps into them. When cover-glass preparations are dried, heated, and stained with the ordinary aniline dyes, these intra-globular bodies stain as readily as nuclei and bacteria, and hold the stain with a similar tenacity. The smallest forms then appear like deeply-stained cocci, about one-half to 1 micromillimeter (boo to ab inch) in diameter, situated within the unstained circle of the corpuscle. Occasion

ally the bodies are nearer 2 micromillimeters (12000 inch) in diame ter, and then the staining may be less intense. Besides the spherical forms ovoid forms are not uncommon. These usually occur in pairs within the red corpuscle. A still rarer pear-shaped form is encountered in stained preparations of the blood. It is rounded at one pole, while the other is pointed and sometimes drawn out as a short filament. These forms quite invariably occurred in pairs, a corpuscle being occupied by a single pair. I am very much inclined to consider the pair as the result of a division of the single body within the globule. One other abnormal form found in the blood deserves mention. When dried cover-glass preparations are stained in Loeffler's alkaline methylene-blue a few red corpuscles appear as if their sur faces had been dusted over with minute specks of coloring matter. Whether they are due to the anæmia or whether they belong to the cycle of the parasite remains to be determined experimentally. As to the relative number of intra-globular bodies in the different organs of the same animal, the eleven cases which have come under observation afford some noteworthy facts. As a rule there are very few in the circulating blood, whether taken from incisions through the skin before or during the death agony or from the heart after death. There are exceptions to this rule, however. In one case they were readily detected in the blood from a skin incision one day before the animal was killed. Blood from the right ventricle showed an enormous number of these bodies in pairs within the red globules. As a rule, then, the circulating blood contains comparatively few parasites. They are filtered out by the spleen and liver. They may be numerous in one or both of these organs, and rare in blood from the right ventricle. They are somewhat more numerous in the spleen than in the liver. This estimate may, however, be erroneous, owing to the larger number of corpuscles in the spleen pulp. There are also a few facts at hand concerning the relative number of parasites in different animals at the time of death. In perhaps one-half of the cases they were so few in number in the spleen that they might have easily escaped the attention of an observer searching for bacteria. In four out of eleven cases the organisms were very numerous in spleen and liver, and could not well be overlooked. They could be seen in a thin layer of fresh spleen pulp, with a dry apochromatic objective giving a magnification not more than 250 diameters. In one case they were so few in number even in the spleen pulp that a number of fields had to be scanned before any were detected. In this case the spleen was completely disintegrated. The urine, containing much hæmoglobin several days before death, was found of nearly normal color at the autopsy. The animal had evidently overpowered the parasites, but died from the havoc caused by them.

The second outbreak of the disease in October was fatal to but two animals. Of the remainder exposed only a few showed signs of disease. When, however, the blood of all the exposed was examined it was found that most of them were affected. The number of blood corpuscles had fallen to one-third or one-fourth of the normal; in one case to one seventh. They presented all the appearances characteristic of Texas fever blood.

The nature of the bodies found within the red corpuscles can only remain a subject of conjecture at the present stage of the investigations, and it is evidently useless to present the various theories which we might hold in regard to them.

The work of the summer, besides having gotten under way experi ments which are destined to clear up the external characters of the disease so mysterious and so unlike other known diseases of man or animals, has elucidated a few very important facts concerning the nature and diagnosis.of the disease.

(1) It has demonstrated that Texas fever is essentially a blood disease, and that all the symptoms and lesions are referable to the destruction of red corpuscles. The disease may appear in two forms, an acute fatal and a mild form. The former, occurring in summer, is characterized by the sudden enormous destruction of corpuscles. The waste products resulting from this destruction clog up the liver, disintegrate the spleen, and lastly pass out unchanged through the kidneys, producing the "red water" or hæmoglobinuria. The mild form, occurring late in the season, is characterized by a moderate destruction of red corpuscles. The waste products are readily transformed without deranging the vital organs. The resulting anæmia gradually disappears as cold weather sets in.

(2) It has shown that this destruction of corpuscles is very probably due not to bacteria but to micro-organisms which are found within the red corpuscles and whose life history is still to be worked out.

(3) It will enable any microscopist to demonstrate either during the life of the diseased animal, by examining the blood and counting the red corpuscles, or immediately after death by examining microscopically the spleen or liver tissue, whether the disease is Texas fever or not.

(4) It has shown that animals may be suffering from Texas fever without manifesting any definite symptoms, and that the animal may erroneously be regarded well unless the blood be examined.

ANTHRAX.

In June, 1889, Dr. Wray, an inspector of the Bureau, brought from Mississippi two sealed tubes, one containing blood from a mule which had a large swelling on the under surface of the neck, the other containing blood from a cow which had succumbed to some disease. The blood in the tube from the mule had a very disagreeable odor and contained three different bacteria. They were not pathogenic, and were probably contaminations.

The tube of cow's blood contained but one form, a bacillus. Its peculiar colonies on gelatine and agar, as well as its beautiful flocculent growth in the bottom of tubes of bouillon and its spore-formation, indicated at once that it was the true anthrax bacillus. Inoculation of two mice confirmed the diagnosis. One died within twenty-four hours with no marked internal or external changes. The spleen contained an enormous number of bacilli, the liver and blood less. The second mouse died in forty-eight hours, afflicted with an extensive subcutaneous cedema. The internal organs contained the anthrax bacilli in considerable numbers. Further investigations with this organism were not attempted, owing to the absence of facilities for conducting experiments with material dangerous to man.

The observations definitely prove the existence of anthrax in the Lower Mississippi Valley.

GLANDERS.

During the year the investigations in glanders were continued partly for the purpose of enlarging the work done in 1888 on the

same subject, already published in the report for that year, and partly to confirm the diagnosis made by the veterinarian (Dr. F. L. Kilborne) on suspected horses in the District of Columbia. The investigations confirm those of last year without bringing to light any facts that deserve mention in this place.

INTERSTITIAL PNEUMONIA IN CATTLE.

During the past three years, three lungs came to the laboratory in which only the pleura and the interlobular tissue were affected. The parenchyma was normal, or at most slightly cedematous. The interlobular tissue was represented by firm whitish bands from oneeighth to one-half an inch in diameter. In these bands were cavities varying from the size of a pin's head to a large pea and communicating with one another. Some were empty, some filled with a mold of material similar to that of the bands themselves; some contained a rather thick, semi-liquid, grayish mass. The exudate forming these honeycombed bands was partly cellular, partly fibrinous, in character. The disease of the pleura was the same as that affecting the interlobular tissue.

Of the history of these cases nothing definite could be obtained. The importance of determining whether there are types of lung disease closely simulating the lesions of pleuro-pneumonia, as these did, led to bacteriological investigations of these three cases. In all a micrococcus was found (in the first case none other in fact) in the interlobular exudate, which closely resembled the swine-plague germ. The general distribution of this germ throughout the exudate in different parts of the lung leads to the inference that it was the cause of the disease. Its pathogenic properties confirm this view. Subcutaneous inoculation destroys rabbits in less than twenty-four hours.

Injection of bouillon cultures through the chest wall into the lungs. of two calves produced a septicemia fatal in less than twenty-four hours.

The bacteria can not be distinguished from those of swine plague, excepting, perhaps, in one particular. In bouillon cultures not more than twenty-four hours old a distinct capsule may be seen around each germ when the culture is examined fresh in a hanging drop. The bacteria on the edge of the drop do not touch one another, and the capsules can be distinctly made out as the cause of this separation. In subsequent cultures they are not to be seen.

The significance of this disease and the bacteria associated with it, as well as its relation to pleuro-pneumonia, can not be interpreted with the aid of the meager material and the incomplete histories of the cases examined. The lesions suggest pleuro-pneumonia, while the presence of specific bacteria separates this disease from pleuropneumonia in which no bacteria have hitherto been found. It is not improbable that the isolated and rare occurrence of this affection constitutes it a disease of septic origin. The localization of the disease points to an infection from the blood and lymph channels and not from the air. The bacteriological observations briefly sketched will enable us in the future to differentiate this lung disease from pleuro-pneumonia, provided the disease is at its height when the animal is killed and the lung perfectly fresh when presented for examination.

TUBERCULOSIS IN DOMESTICATED ANIMALS.*

Tuberculosis is an infectious disease of man and the lower animals, the term infectious being applied to all diseases due to the presence of micro-organisms. It is moreover an infectious disease of the contagious type; that is, it is communicable from one person or animal to another. The infectious nature of tuberculosis was, however, not fully recognized until demonstrated by Villemin in 1864. He showed that the inoculation of the cheesy matter found in the tubercles was followed by the appearance of similer tubercles in the inoculated animals, in other words, by the disease itself. Perhaps the most important advance in our knowledge of the disease as a whole was the discovery of the bacillus tuberculosis by R. Koch, in 1882. Before this time there existed much difference of opinion concerning the identity or non-identity of tuberculosis in man and in the lower animals. The discovery of the same bacillus in the various forms. of the disease in man and animals practically settled this question, and it is now generally believed that tuberculosis in man and in the domesticated animals is the varied expression of the same disease.

The wide distribution of the disease among cattle, as well as the large percentage of animals diseased, has led to a great activity in the study of the disease in all its bearings. The most important questions now before the public are: (1) How can the disease be restricted among the domesticated animals? (2) Are human beings infected by consuming the flesh and milk of tuberculous animals, and if so, to what extent? Before briefly discussing these two practical questions a few preliminary subjects demand our attention.

THE GENERAL CHARACTER OF THE DISEASE.

As its name implies, the disease is characterized by the formation, in different organs of the body, of certain nodules or tubercles of varying size. They consist of cellular elements crowded together, and owing to the absence of blood vessels they soon die for want of nutriment, and are converted into cheesy masses often impregnated with calcareous particles. The increase in size of these tubercles crowding upon and destroying the surrounding tissue of the internal organs, and the subsequent breaking down into cheesy matter, may be considered the chief injury inflicted upon the body by the disease. The tubercles are not limited to any particular region or organ of the body. Though they seem to show predilection for certain organs, which predilection varies with the species of animals affected, they may appear in almost any organ. Often beginning in some one locality, the tubercles there formed enlarge, become cheesy, and the virus lodged in this cheesy substance may be carried into other regions of the body. Sometimes the tubercle discharges the cheesy matter into a blood-vessel. It becomes disseminated throughout the body by the circulating blood, and wherever it lodges a new crop of tubercles appears in course of time.

The infection residing in the tubercle is due to a bacillus discovered by R. Koch in 1882, and demonstrated by him as the specific cause of the disease. This bacillus is a slender rod-shaped body, from 17000 to

*Consult also Dr. James Law's report on tuberculosis as discussed at the International Veterinary Congress held at Brussels in 1883. First annual report of the Bureau of Animal Industry (1884), p. 350-366.