PRESIDENTIAL ADDRESS. (e3: 
in some specimens examined by us it is safe to say that in 
the affected areas the weight of these leprosy bacilli was 
ereater than that of the tissue they were invading. This 
condition in rats meets its parallel in certain cases of nodu- 
lar leprosy of human beings; in these lepromata the lep- 
rosy bacilli may be present in enormous numbers. The 
first leprous rat recorded for Australia was found in Syd- 
ney on 20th April, 1904." In May, 1910,? another infected 
rat (Hpimys norvegicus) was found at Ultimo. Further 
leprous rats were found in Sydney on 4th December, 1911, 
11th January, 1912, and 22nd August, 1912.2 From two of 
these rats successful inoculations were made into white rats. 
Up to the period when the last of these rats was found by 
us about 560,000 rats and mice had been examined during 
the previous 14 years, and five of the rats were found 
severely affected with this disease. From this it might be 
inferred that one diseased rat might be expected in Sydney 
in about 100,000 examined. 
In 1918 Dr. Priestley (Australasian Medical Gazette, 
Nov., 1918, p. 405) recorded the presence of these acid- 
fast bacilli in rats (E. norvegicus) in the Townsville dis- 
trict. Of 220 rats examined, 6 had the lymphatic form of 
the infection, 6 the musculo-cutaneous type found in the 
above-mentioned Sydney rats. The incidence amongst 
these North Queensland rats is much higher than in the 
New South Wales ones. In 1907, Dr. R. J. Bull* recorded 
a case from Collingwood, Melbourne. Ll. B. Bull reported 
the occurrence of a case in South Australia to the chair- 
man of the Adelaide Local Board of Health a few years ago. 
» Report of the Board of Health on Leprosy in New South Wales, 1904 
. 13 
a eeeodd Report of the Government Bureau of Microbiology, 1910- 
1911, p. 49. 
* Fourth Report of the Microbiological Laboratory, Dept. of Public 
Health, 1913, p. 186. 
# Intercol, Med. J. of Austr., May, 1907. 
