ORGANISMS WHICH PRODUCE DISEASE 81 



differently prepared vaccines, usually spoken of as tuberculins, 

 have been and are being extensively used both for diagnosis 

 and treatment. What is known as Koch's Old Tuberculin is 

 prepared either from the human or the bovine bacillus by 

 sterilising, concentrating, and filtering a glycerin-broth culture 

 of tho bacillus ; and is used extensively for the diagnostic 

 Tuberculin Test in both man and animals. Scarification, 

 inunction as an ointment, and subcutaneous injection methods 

 each have their advocates. The last-named method is that 

 used in the testing of cattle, Perlsucht Tuberculin (i.e. that 

 prepared from the bovine bacillus) being used. In some" 

 advanced cases of the disease, both in man and in animals, 

 the test may give a negative result, and another possible 

 source of fallacy unfortunately sometimes made use of by 

 unscrupulous dealers arises from the fact that, even in a 

 diseased animal, a previous inoculation with tuberculin may 

 prevent the appearance of a positive reaction. 



With regard to the therapeutic use of the tuberculins, it 

 can only be said that in suitable, and especially in early, com- 

 paratively non-progressive localised cases of the disease where 

 there is no fever, and when given with scrupulous care as 

 regards the graduation of its dosage, it may be regarded as an 

 adjuvant to other treatment. In progressive and especially 

 in advanced cases, and if too large doses are used, it may do 

 infinite harm, producing increased activity, even in old and 

 partially healed lesions, and lighting up, it may be, a general- 

 ised and rapidly fatal tuberculosis. 



Treatment with antituberculous sera has also been used, but 

 is still more or less unsatisfactory and in its experimental stage. 



Bacillus leprae is the cause of Leprosy, an infective and 

 contagious disease characterised by its slow onset and chronic 

 course, and the terrible disfigurements and mutilations which 

 it produces in its victims. The disease, which has been 

 known from the most ancient times, was once widely spread 

 over the globe, but is now rather tropical and sub-tropical 

 in its distribution, though still also found in Norway, Russia, 

 Newfoundland, and elsewhere. It used formerly to be endemic 

 in this country, but has now been stamped out, though one or 

 two cases in persons who have never been out of the country 

 have been reported. The lesions are characterised by destruc- 

 tion and absorption of the tissues, with a certain amount 

 of fibrous formation. The disease may attack any organ or 

 tissue, but is specially found in the skin and subcutaneous 

 tissues, mucous membranes (e.g. of the eye, nose, etc.), the 

 various glands of the body, and the trunks of nerves, especi- 



