BUREAU OF ANIMAL, INDUSTRY. 239 



AUTOPSIES ON WILD ANIMALS. 



The National Zoological Park continues to furnish quite an 

 important percentage of the necropsies made by the Pathological 

 Division. During the past fiscal year 114 animals, including mam- 

 mals, birds, and reptiles, were received from this source. The results 

 of post-mortem examination, as in previous years, show the frequent 

 occurrence of digestive and respiratory disorders, diseased conditions 

 involving these systems outnumbering all other affections combined. 

 While lack of sufficient exercise and unaccustomed chmatic conditions 

 are important predisposing factors, the active agents in numerous 

 instances were specifically determined. Mycosis of the lungs as a con- 

 sequence of aspergillus invasion was particularly destructive to birds, 

 as were also intestinal disorders of protozoan origin. The presence 

 of parasites was not infrequently associated with gastric and intes- 

 tinal lesions. Of the bacterial diseases, tuberculosis continued to be 

 a menacing factor at the park. Autopsies indicate that monkeys are 

 especially susceptible to this disease. 



SKIN DISEASES IN SWINE. 



The work at the branch pathological laboratory located at Chicago, 

 111., has steadily increased. During the past year a large number of 

 specimens have been forwarded by inspectors located at this and trib- 

 utary stations for diagnosis. 



Two interesting conditions of the skin of swine have been studied. 

 One is that of naevi pigmentosi. These naevi, or pigmented moles, 

 are congenital and are seen most frequently in black swine, although 

 red and spotted animals are not exempt. They appear as inky black, 

 irregularly round spots, from one-eighth to one-half inch in diameter. 

 In some cases they may be much larger; in such cases they are ele- 

 vated and are covered with stiff, coarse hair, which grows straight 

 outward. The usual location is in the skin over the back and 

 hams, although they may affect the skin on any part of the body. 

 Usually only a few" spots are present, but occasionally an animal is 

 found where they are quite numerous. Inspectors on the killing 

 floors of slaughterhouses report that from 16 to 19 per cent of the 

 hogs are affected. If the small black spots are in-cised, it will be 

 found that there is a black semifluid pigment deposited between the 

 layers of the skin, while in the larger spots the pigment may extend 

 into the fat beneath. 



The other condition is that of elephantiasis papillomatosa. In this 

 condition there is a marked hypertrophy of the papillary layer of 

 the skin involving all or part of the surface of the body. The skin of 

 animals so affected is much thickened and very rough, and gives lodg- 

 ment to sebaceous material and dirt. When the elephantiasis 

 extends all over the body there are deep wrinkles over the head and 

 neck, also on the sides. Animals so affected are called "mangy 

 hogs" by those engaged in buying hogs. So far the etiology has not 

 been determined, but the affection is evidently not of a contagious 

 nature. 



BLACKLEG INVESTIGATIONS. 



During the fiscal year the Pathological Division has prepared foi 

 free distribution over 1,000,000 doses of blackleg vaccine. With the 



