178 MR. J. B. SUTTON ON THK [Mar. 18, 



one of them. Two Hysenas succumbed in a similar manner. Two 

 Black-faced Kangaroos died within forty-eight hours of each other. 

 Two Foxes were brought to the dissecting room within twenty-four 

 hours ; and of this sort of thing many instances among smaller 

 mammals might be given, so as to carry it out of the domain of 

 coincidence. 



For some considerable time the suspicion of the existence of some 

 acute specific disease contagious in its nature has held possession of 

 my mind. More than once a singular feeling of languor and uncon- 

 trollable depression, accompanied with weariness, has seized me after 

 conducting the necessary dissection on the animals dying after this 

 manner, so that of late I have been more cautious than heretofore. 



Let me now pass on to consider the various diseases in detail ; they 

 will be treated in the following order : — 



1st, Those affecting the skeleton ; 2nd, Diseases of the Organs 

 of Respiration ; 3rd, Affections of the Circulatory System ; 4th, 

 Diseases of the Alimentary Canal and the Viscera appertaining 

 tliereto ; 5th, the Genito-urinary Organs ; 6th, Tuberculosis, which, 

 for various reasons to be explained later on, has been made a separate 

 segment, instead of treating it along with diseases of the respi- 

 ratory organs. 



Diseases affectiny the Skeleton. 



1. Rickets. — This disease has been encountered many times, but 

 its ravages are most severely seen among the smaller Carnivora. The 

 affection is met with in two very distinct forms — " rickets of infancy " 

 and " late rickets " occurring at puberty. 



a. Rickets of Infancy. — The chief symptoms are deformity of the 

 long bones and paralysis of the hinder limbs (paraplegia). Death 

 usually results from some intercurrent malady, generally bronchitis, 

 which is a very dangerous complication of rickets, on account of the 

 softened ribs yielding to atmospheric pressure, ending in collapse of 

 the lungs. 



In this form of the disease, the skeleton is affected throughout. 

 The thorax is deformed, there is beading of the ribs at their junction 

 with the costal cartilages, and a second row of beads immediately 

 external to the angles of the ribs : these are caused by partial frac- 

 ture (infractions) of the softened ribs, and the abundant formation 

 of provisional callus at the seat of injury. This is a very constant 

 feature of the disease in Carnivora, but it may be confined to one 

 side. This double row of rickety beads is shown in the drawing 

 (fig. 1, p. 179). The skull is thin, soft, and in some places 

 absorbed. The teeth are normal in size, number, and development. 



The long bones of the limbs are curved, enlarged, and so soft that 

 they may be cut with a knife easily. The periosteum is usually 

 thicker than normal. The hne of the epiphysial cartilage to the 

 naked eye presents enlargement, irregularity, and abundance of 

 the curious translucent gelatinous substance known as spongioid 

 tissue, so eminently characteristic of rickets. Submitted to the 

 scrutiny of the microscope, the following changes may be observed : — 



