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

There is no

hyphæ arise, with perfect sterigmata and spores. 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 (X 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

same nodule as they are taken further and further away from the centre. In general the fungus is thickest at the centre, so thick in many instances that the lung-tissue is hidden entirely, and grows less as we go outward. The tissue changes

noted, formation of fibrin, etc., take place in a zone beyond the greatest growth of the fungus. In other nodules the fungus is evenly distributed throughout, following the alveolar walls. In these the tissue changes are slight. At times the

fungus grows in dense brush-like clusters, closely resembling actinontycosis under a low magnification. (See Fig. 3.) This form is considered to show a marked reaction and resistance on the part of the animal, and a lowered vitality in the fungus.

A section through nodule in lung, showing brush-like forms and mycelium in cross section. Stained by Lithium carmine and Weigert's fibrin method. X 150.

When found it indicates that the aspergillosis is a primary and not a secondary or terminal affection. No giant cells were found in any section.

Fruit formation was not observed in the substance of the tissues at any time. It was observed most frequently in