584 MR. J. B. SUTTON ON THE DISEASES OF MONKEYS. [DeC. 4, 



briefly enumerated as deformity, pain, paraplegia, iucoutiuence of 

 urine and faeces. Dr. Percy, in the paper before alluded to, states 

 that some of bis Monkeys died from moUities ossium, the symptoms 

 being deformity and paralysis. 



The condition of the skeleton in such cases is very remarkable. 

 The bones are enlarged, and so soft that they can be cut with a knife 

 as easily as a potato ; in severe cases not a bone escapes, not even 

 the hyoid ; indeed they exhibit in an extreme degree the pathological 

 condition met with in rickets as it occurs in young children. I find 

 the disease has two opposite effects on the skull. In most Monkeys 

 the bones of the cranium soften and in parts undergo thinning ; 

 sometimes they atrophy so as to give rise to actual perforation of 

 the skull : this condition is most frequently observed in the cerebellar 

 fossae and roof of the orbit ; now and then it is seen on the roof 

 of the skull. In other Monkeys, chiefly the Baboons, the skull- 

 bones thicken. In some cases I have observed the roof of the skull 

 to be as much as half an inch in thickness. A complete account 

 of the pathology and microscopic appearances of the various parts of 

 the skeleton in these cases will be found in the Transactions of the 

 Pathological Society, volume xxxiv. 



There yet remains the paralysis to be accounted for ; this symptom 

 perplexed me extremely, but I am now able to give a satisfactory 

 explanation of it. 



The 'Journal de Zoologie' for 1875 (iv. p. 2/2) contains an in- 

 teresting article by Paul Gervais, entitled " De I'hyperostoze chez 

 I'homme et les animaux." Among the specimens there figured is a 

 vertebra from an animal named Pachyacanthus dug up near Vienna. 

 It is a very singular specimen, and shows a condition which is very 

 rarely met with, viz. gradual general obliteration of the spinal canal 

 due to overgrowth of bone. This supplied the hint, and I divided 

 the spinal column in all rickety Monkeys. This is what I found : — 

 The general overgrowth and softening of bone so common throughout 

 the skeleton had not spared the vertebrae with its various processes, 

 but they had enlarged and encroached upon the spinal canal and 

 thus exercised general slow compression upon the spinal cord. When 

 the creature stands, the pressure of the superincumbent weight 

 would cause the vertebral bodies to bulge and compress still more 

 the spinal cord and nerves as they emerge from the various inter- 

 vertebral foramina, hence the pain when the creature is raised ; 

 the continuous irritation of the lumbar spinal cord will also explain 

 the incontinence and priapism. I am not aware of any recorded 

 cases of such general narrowing of the neural canal ; and it is easy 

 to explain why it has been overlooked, for it is usual to expose the 

 cord by removal of the vertebral arches, thus destroying the relative 

 size of the cord to the spinal canal ; whereas if a transverse section 

 of the column be made with the cord in situ, the change is obvious. 

 The cord and nerves when examined microscopically exhibit all the 

 changes found in the grey and white matter when the cord has been 

 compressed from other causes, such as cancer, tumour, vertebral 

 caries, &c. It is very probable that the agonizing pains which form 



