KEPOKT OF THE SECRETARY. 47 



immune to hog cholera, and it seems evident that pigs from such 

 sows are themselves immune at birth and that this immunity lasts 

 for at least three weeks. 



INVESTIGATION OF OTHER ANIMAL DISEASES. 



The scientific staff of the Bureau of Animal Industry has continued 

 the investigation of the causes and nature of various diseases of live 

 stock. Perhaps the most important work of the j'-ear has been that 

 relating to infectious abortion. This disease rivals tuberculosis as 

 a plague of the cattle industry. The germs causing infectious abor- 

 tion frequently occur in milk, and have also been found in the tonsils 

 of children, where they have probably been conveyed by milk. In- 

 oculation experiments show that these germs have the power to pro- 

 duce distinct lesions in guinea pigs. Just what effect this organism 

 may have on human health has not yet been determined, but our 

 present knowledge seems to afford another reason for the pasteur- 

 ization of milk as a safeguard against various infectious diseases. 



What is known as the complement-fixation test has been found to 

 be an exceedingly reliable and prompt means of diagnosing certain 

 diseases the determination of which has hitherto been attended with 

 some uncertainty and delay. The bureau has extended the use of 

 this test to a number of diseases. 



That rabies (or hydrophobia) is a continued menace is shown by 

 the fact that 183 animals suspected of having this disease were sent 

 to the pathological laboratory for diagnosis, of Avhich 112 cases were 

 found to be positive. While most of the cases occur in dogs, an 

 unusually large proportion of cats were received. The best known 

 means of getting rid of this disease is the muzzling of all dogs for a 

 sufficient period. Muzzling orders are sometimes issued, but it is 

 difficult to secure their thorough enforcement. 



Among other diseases concerning which investigations were made 

 during the year are forage poisoning, or cerebrospinal meningitis, 

 swamp fever, dourine, tetanus, chronic mastitis, and Malta fever. 

 It seems that the latter disease has existed among goats in Texas and 

 New Mexico for many years. It is passive in goats, but causes seri- 

 ous illness in man, to whoui it is communicated from the goats. It 

 is important that steps should be taken to eradicate this disease from 

 the goats, especially since there is a growing tendency to use goats' 

 milk as food for infants and invalids. The infection of man may 

 be guarded against by pasteurizing goats' milk where there is any, 

 reason to suspect that the infection may be present. 



DISTRIBUTION OF VACCINE, ETC. 



During the year 1,340,380 doses of blackk^g vaccine were prepared 

 and distributed to stock raisers by the Bureau of Animal Industry. 



