2 7 8 



Scientific Proceedings (116). 



The gross evidences of rickets in the rats eating the faulty 

 ration were briefly these: deformities of the thorax consisting in 

 flattening or hollowing along the line of costochondral junctions; 

 pigeon breast; enlargement and distortion of the costochondral 

 junctions; fractures of the ribs; enlargements of the ends of all 

 the long bones; diminished resistance of the bone to cutting; 

 great diminution in the tensile strength; and finally, the presence 

 of a zone of a white or pale yellow color, between the cartilage and 

 the shaft, visible to the naked eye, the rachitic metaphysis. 



The microscopic evidences of rickets in the skeleton of the rats 

 receiving the diet were convincing. There was increased thick- 

 ness and great irregularity of the proliferative cartilage which ex- 

 tended in irregular prolongations toward the shaft, complete ab- 

 sence of calcium deposition in the cartilage or great defects in 

 calcification, the presence of an intermediate zone between cartilage 

 and shaft, the zone already alluded to as the rachitic metaphysis, 

 composed of cartilage in all stages in the process of metaplasia into 

 osteoid, osteoid trabecular, blood vessels accompanied by marrow 

 elements, irregular deposits of calcified intercellular substance 

 encased in osteoid and, finally, by broad osteoid investments of the 

 trabecular of the shaft. The condition in the bone produced by 

 the faulty diet in question may be said to have been at all points 

 identical with that seen in advanced rachitis of human beings. 



When now butter fat was added to the faulty diet just dis- 

 cussed in the proportion of 0.5 per cent, of the total ration, the 

 occurrence of the xerophthalmia was somewhat postponed and 

 the life of the animal lengthened. The pathological condition of 

 the skeleton, however, remained essentially unmodified. If any- 

 thing, it was intensified, probably as the result of the slight stimu- 

 lation given by the butter fat to the growth of the bone. 



When butter fat was added in the proportion of 10 per cent, of 

 the total ration, the occurrence of the ophthalmia was effectually 

 prevented, life was prolonged for a number of months and the 

 pathological condition in the skeleton was somewhat modified but 

 still remained rickets (observations on four rats). In one animal, 

 light but uniform calcification in the zone of cartilage nearest the 

 shaft was present. In all four rats the metaphysis was exceedingly 

 deep and composed in greater part of interlacing osteoid trabecular 



