856 PROF. T. WINGATE TODD ON OSTEOMALACIA. 



and rats than in monkeys. The disease seems to localize itself 

 in different sites in different animals. In the macaqnes and 

 baboons it usually affects the hind limbs, which are in con- 

 sequence badly bent and twisted, but that the whole skeleton is 

 affected is shown by the brittle character of all the bones. The 

 ability of the bones to unite after fi-acture does not seem to be 

 impaired. Fig. 4 (PI. LXXXVIII.) represents the tibia of a 

 young Anubis Baboon [Gynocephalus aniohis) after healing of 

 a fracture near the upper extremity. This bone was broken 

 by a fall from a height of some three feet while the animal was 

 attempting to escape from a pursuer. The animals may become 

 affected by the disease while still young and before the epijahj'ses 

 have joined, so that the disease is readily confounded with rickets. 

 The lesions, however, are the same at whatever age the disease 

 occurs. In some instances the bone-changes are found most 

 marked in the foi-e limbs. This was the case in a peccary from the 

 Manchester Collection. The animal struggled about with its fore 

 limbs bent backwards beneath the body. In other animals the 

 bones of the face are affected. The maxillae are much enlarged 

 and give a puffed-out appearance to the cheeks. This condition 

 occurred in a horse, a leopard, a rabbit, and a chimpanzee. In 

 some cases the necks of the teeth are decayed and the teeth may 

 fall out. This was observed in the leopard and rabbit just 

 referred to, and also in a Californian sea-lion from Cleveland. 

 Ulceration and falling of the teeth has not occurred among 

 the apes in Manchester since the glass was taken out of the 

 windows of the monkey-house. The bones of the chest are 

 frequently softened and deformed, which would seem to pre- 

 dispose the animal to respiratory disorders. The lungs of the 

 sea-lion showed emphysema and patches of broncho-pneumonia, 

 the latter being confirmed by histological examination. 



Post mortem, the viscera show no lesion whatever in animals 

 which have been intentionally killed. Nor are there any atrophic 

 changes in the muscles of the disabled limbs. 



The ductless glands are ajjparently normal. Pathological 

 appearances are to be found only in the nervous system and 

 the bones. As regards the former opinion is very varied. Gayet 

 and Bonnet describe an increase in volume of the nerves with 

 an overgrowth of the fibrous tissue between the nerve-bundles 

 a.nd disappearance of myelin in certain cases. The blood-vessels 

 of the nerves exhibit endarteritis (1). They found no cellular 

 lesion nor any alteration in nerve-fibres in the spinal cord. 

 Morpurgo, on the other hand, describes diffuse chromatolysis 

 in the cells of the anterior horns of the cord, but denies any 

 change in the cells of the spinal ganglia (2). These changes 

 occur very early in the course of the disease, but there would 

 appear to be no definite evidence to show that they initiated the 

 disease (3). 



It ma,y be that these different histological pictures were 



