576 
Proceedings of the Royal Society of Edinburgh. [Sess. 
a matter for surprise, and affords a ready explanation of the fact that after 
most careful treatment of an experimental animal by any of the approved 
methods of immunisation, the administration of a suitable quantum of 
M. melitensis culture is invariably followed by infection. These remarks 
hold good in the case of adult animals of all other orders of mammals, in- 
cluding monkeys — despite Shaw’s opinion to the contrary, which was based 
upon experiments made whilst he was still unaware of the fact that a type 
of infection could be produced in the monkey resembling the ambulatory 
