Pneumonokoniosis, because of its importance in industrial diseases, has been subjected during recent years to considerable intensive study in human medicine, from which activity some interesting and useful information has been obtained as to its genesis and effect upon the function of the lung. This condition is of course a purely environmental one, the degree and particular kind of “dusting” being dependent upon the duration and nature of exposure of the particular individual. This Garden is situated beside an active railroad trunk line so that the opportunity for coal dust inhalation is continuous. The degree of anthracotic pigmentation of the lungs and related serous membranes is really negligible and with one questionable exception, we have not seen fibrosis due to this cause in any animal. The one exception, an amazon presented and living in the Garden but three months, at necropsy showed an interstitial chronic bronchitis and pneumonitis stretching out from the hilum, all of the affected area being deeply pigmented. The picture was comparable to what might be expected from a second degree anthracotic fibrosis of Landis and Pancoast. Many specimens come to autopsy with some grade of pigmentation, but none, except the one above, with resultant fibrosis. The degree of anthracosis is usually so slight that it has been considered important enough to include in the diagnosis but eighteen times and curiously enough seventeen of these were observed in birds. Were there more cases it might be profitable to plot their exhibition period but the use of this small number might lead to error; the average length of exhibition of the birds was about a year. It is common to observe some black specklings of the air sacs, as if pepper were dusted on them as has been said before, but even this is rarely marked. It is most often seen in the Anseres, Psittaci and Struthiones but a goodly number of cases occur in the long-lived Passeres. The distribution of the pigment is essentially the same throughout Mammalia—peribronchial, submucous and in the lymph nodes at the root of the lung. In the birds it is first seen in the subepithelial spaces of the septa of the small alveoli where they project into the secondaries, later accumulating in the connective tissue of the main septa. Collections under the pleura and at the root of the lung are rare, the dust usually spreading out along the air passages into the air sacs. Other forms of pneumonokoniosis are unknown. Although animals must inspire much dust from dry feed and from floors it must be caught early and removed by snorting or by the lymphatic drainage. It seems fairly well accepted that dusts are dangerous to the degree that they contain inorganic substance and as these animals are not exposed to concentrated mineral or metallic dusts, no effects are seen. INFARCTION OF LUNG.