238 ANNUAL REPORTS OF DEPARTMENT OF AGRICULTURE. 



instances tluiii in previous yetirs, and has been employed then only in 

 cases where {U)gs have inlhcted wounds on persons or animals and 

 a satisfactory diaf^nosis could not bo made by the detection of Negri 

 bo(Ues. In cases wlicre the snsper-t iuflicUul no injury to man or 

 bciist only the examination i'or Xc^ri botUes was conducted. 



During the vear there w^ere examined the brains of 152 dogs, 9 cats, 

 1 goat, 8 cattle, 2 hogs, and 1 horse, a total of 173 cases. Of these 

 there wore found to have been afTected wMth rabies 117 dogs, 4 cats, 

 7 cattle, 1 goat, and 1 horse, a total of 130 cases. Of these positive 

 cases 75 came from the District of Columbia, 25 from Virginia, 21 from 

 Maryland, 3 from West Virginia, 2 from New York, 2 from Kentucky, 

 1 from New Jersey, and 1 from Tennessee. 



SO-CALLED "black TONGUE " OF DOGS. 



The bureau has received several reports of the existence of a dis- 

 ease termed "black tongue" among dogs, which appeared to be of an 

 infectious nature and almost invariably fatal. The disease exists 

 principally in the Southern States. Hunting dogs are most fre- 

 quently afTected, and pet animals and common dogs are also sus- 

 ceptible; but it appears that the infection prevails to a greater extent 

 in the fields, woods, or ])astures, which ex,{Hains the greater frequency 

 of the disease among sporting dogs. The symptoms as described in 

 the reports are not of a uniform character, although it is evident that 

 in most instances the predominating manifestations are the lesions 

 in the mouth. The dark discoloration of the tongue appears to be a 

 constant symptom. Other lesions in the mouth may consist of a 

 swelling and reddening of the mucous membrane with erosions and 

 even ulceration. These lesions are most often found around the 

 frenum of the tongue and on the gums and cheeks. The inflamma- 

 tion of the mucous membrane frequently extends to the stomach and 

 intestines, in which the mucous membrane discloses a severe catarrhal 

 inflammation. The affected animals lose strength rapidly and die 

 within a few days from the onset of the disease. Recoveries may 

 occur in exceptional cases. 



One form of so-caUed black tongue has been studied in the labora- 

 tories of the Pathological Division. In this instance it afl'ected sev- 

 eral animals of a Mexican breed. The symptoms appeared as 

 described above, and a bacteriological examination of the lesions 

 revealed the presence of Bacillus necrophorus. A treatment with 

 antiseptic mouth washes and intestinal disinfection appeared to give 

 beneficial results, and thorough and repeated disinfection of the prem- 

 ises prevented the infection among the remaining healthy dogs. 



The term "black tongue" as a name for any disease is unfounded, 

 as this simply represents a symptom which may be present in various 

 diseases such as dumb rabies, distemper, Stuttgart disease (typhus 

 canum), necrobacillosis, certain forms of pneumonia, etc. It simply 

 implies a dark discoloration of the mucous membrane of the tongue, 

 w^hich may result from various causes. Thus, for instance, in dumb 

 rabies the dryness of the tongue and the accumulation of dirt on its 

 surface give it the peculiar dark appearance; in other diseases a 

 cyanotic condition may be responsible for the discoloration. 



Requests have been made through different sources for material for 

 the further study of the disease existing among the dogs of the South, 

 and it is hoped that it will be possible to discover the nature and 

 successful treatment of the disease. 



