The aspergillus fumigatus is differentiated from other species by its color in cultures, the high temperature at which it grows, the size of its spores, and by its pathogenic power. In practice the aspergillus glaucus is the one most likely to be confounded with it, but it may be recognized by its ability to grow at low temperatures, its delicate green color, the large size of its spores-9μ to 15μ in diameter-and its lack of pathogenic power.

Case. The animal under consideration was a Jersey cow, six years old. She was bred and raised on a farm near Philadelphia, and was never off of this farm until sent to the Veterinary Hospital a short time before she died. The herd of which this cow was a member numbers about eighty animals. The milking-cows are kept in the basement of a large stone barn. The cow-stable is lighted on three sides, but not in such a way as to allow the rays of the sun to reach more than a small fraction of it. The cows are fed from an artificial-stone floor, and are confined in stanchions with no partition to separate them from one another. The hay is thrown down into the stable from a loft above. The floor is frequently strewn with land-plaster, and the atmosphere of the stable is often loaded with dust.

This cow was in bad condition for six months; she was not thrifty, her coat was rough, the skin tight, the nutritive condition bad. During the last two months emaciation was more rapid, and the animal coughed considerably, especially after eating. The cough was dry and harsh. The appetite continued, but the flow of milk diminished to about one-fourth of the previous volume. Suspecting tuberculosis, she was tested with tuberculin, but gave no reaction. She was treated with tonics, but did not improve; on the contrary, her condition became worse, and about two weeks after the test an obstinate diarrhoea developed that could not be controlled by the ordinary farm-treatment, and the owner concluding that the cow was worthless decided that he would destroy her. In order that the animal might be observed more closely a request was made that it should be sent to the Veterinary Hospital of the University of Pennsylvania. This was done. Upon arrival at the hospital it was found that the cow would not eat, and she was weak and depressed; respirations labored, and from forty to sixty per minute; pulse rapid. Percussion of the chest-walls gave a sound that, if anything, was clearer and louder than the normal percussion sound. Upon auscul

tation it was found that the vesicular and bronchial murmurs were considerably increased in intensity and accompanied here and there by sibilant râles. The cow coughed violently at times. Six days after she came to the hospital the breathing became more rapid and difficult, and the pulse very much accelerated. The animal did not eat, grew weak rapidly, and died four days later, or ten days after admission to the hospital.

Autopsy. The animal was much emaciated. The mucous membrane of the small intestine was catarrhal and showed a small amount of erosion. All the organs were normal except the

lungs, one of which was removed to the laboratory for minute examination. The most striking feature on external examination was the extreme amount of emphysema. The lobules were separated from each other as much as 3 to 5 millimetres, and even at some distance from the borders light could be seen through these crevices on holding the lung up before the eyes. On the surface the subpleural connective-tissue was distended

in large blebs. Upon palpation the lung crackled, and numerous hard nodules could be felt. On section a curious picture was presented, numerous dark-red nodules being seen, the surrounding lung appearing normal in color. In each lung there were from fifty to sixty of these nodules, from 5 to 12 millimetres in diameter, most of them dark red, and closely resembling partially organized blood-clots. However, on crushing a por

tion in glycerin between two slides and examining under the microscope, they were found to be made up almost entirely of a felted network of mycelial threads. Between these large nodules were numberless smaller areas of the same color, 1 to 2 millimetres in diameter, not perceptible to the touch as nodules, but which were of the same character, and were, no doubt, foci of recent origin. These were seen especially well in por

tions of the lung which were preserved by Pick's method, the slight bleaching of the tissues bringing them into relief. On opening some of the interlobular emphysematous spaces small whitish mouldy-looking patches were noticed on nodules which bordered the cavity. Scrapings from these patches were made up entirely of perfect fruit hyphæ with myriads of spores. (See Figs. 1 and 2.) The diagnosis of a mould mycosis was in this way made at once and confirmed by cultures and examination of sections. Cultures were made on glycerinated potato, bouillon, and plain agar, by opening a nodule with sterile instruments and tearing out a small portion of the centre, which was transferred to the culture-tubes and placed in the incubator at 39° C. Abundant growth was obtained on the potato by the end of thirty-six hours, white at first, and soon changing to yellowish-green, then to dark green. The growth in the bouillon and agar was slow. Plates and flasks of bread-paste were made, and these, with potato, were employed for all subsequent cultures. The formation of the fruit-hyphae was studied, and the spores measured a number of times, being from 2.5μ to 3.5μ in diameter. By these means the culture was identified as the aspergillus fumigatus.

Our experiments on animals were limited to the inoculation of one rabbit, in the aural vein of which one-half cubic centimetre of a suspension of the spores was injected. The animal died in forty-four hours, and from the liver and kidneys cultures were recovered. All of the organs were examined in sections, but only in the same two was mycelium detected.

Microscopic examination. The nodules were hardened and embedded, some in celloidin, and some in paraffin. Various staining methods were tried, hæmatoxylin and eosin, carbolthionine, Gram, and lithium carmine with Weigert's fibrinstain. Good results were obtained with all, but the carmine and Weigert gave the most beautiful picture, and by this method the fungus was most perfectly demonstrated, the spores and mycelium taking on a deep purple color. The histological picture was studied mainly in sections stained by hæmatoxylin and eosin. The bronchial epithelium was normal in places, but for the most part the columnar cells have been replaced by a sort of membrane, which appears to be made up almost entirely of a felt-work of mycelial threads. From this membrane hyphæ grow out into the lumen of the bronchus, and here, owing, no doubt, to the supply of air, fruit

hyphæ arise, with perfect sterigmata and spores. There is no cellular nor other exudate and very little débris. The under surface of this membrane is of looser texture, and contains some cellular infiltration made up of round-cells, leucocytes, proliferated connective-cells and red blood-corpuscles. The adjacent structures are closely filled with a cellular infiltration of the same description, with a quantity of mycelium, this extending to the neighboring alveoli, which under a low power (80) appear to have preserved their outline; but with greater amplification (625) are seen to have lost all their normal structure, showing clumps of homogenous, irregular masses, which stain faintly with eosin, and are probably of connective-tissue origin.

In these areas the mycelium has followed the alveolar wall as a trellis, the tissue seeming to oppose no obstacle to its advance. Within the alveoli is a finely granular débris, with some coarser particles, probably the remains of cells. In sections stained with carbol-thionine large numbers of mast-cells are seen in the alveolar walls. Bordering these degenerated areas are alveoli which have retained their normal structure and are filled with a network of fibrin holding in its meshes a few cells-leucocytes and septal cells. In other parts of the sections are areas resembling those just described, but in which all anatomical landmarks have been destroyed, so that it is impossible to tell whether or not the spaces seen are bronchi.

Some sections show a widespread interstitial and alveolar hemorrhage, the blood showing a considerable increase in the number of leucocytes. The capillaries are congested, and areas of oedema with thickening of the alveolar walls are not un

common.

There is peri-bronchitis and arteritis, while in some sections arterial thrombosis is seen, the thrombus being penetrated by mycelium, though no fruit is found. Areas are also found in which the alveoli are filled with a cellular exudate producing consolidation and thickening of the alveolar walls.

Emphysema, both interstitial and vesicular, is marked, and often extreme. Around the borders of the interstitial cavities is a distinct zone made up of red blood-cells, leucocytes, and a homogeneous material, which is yellowish in fresh as well as in stained sections. The areas contain very little mycelium. All sections show a small amount of anthracosis. The appearance of sections varies in different nodules, and in the