282 Proceedings of Royal Society of Edinburgh. [sess. 
Scapula and Clavicle. — Both these hones were slightly below 
the normal size — 
Spec. Normal. 
Clavicle — total length, . . 3*7 4*5 
Scapula — height, . . . 4*2 4-4 
„ greatest breadth, . . 2*3 2*6 
Microscopical appearances observed in the different Bones of the 
Skeleton. — After hardening in Muller’s fluid, the bones were decalci- 
fied in “ Perenje ” and embedded in paraffin. Complete sections 
were then cut with the large microtome, and mounted in approxi- 
mate series. 
Before entering into details, we may state at once that we found 
no evidence whatsoever of any disease known to affect the foetal 
skeleton, e.g ., syphilis, rickets. The essential lesion showed itself as 
an absence, arrest, or perversion of the normal process of endo- 
chondral ossification of the most definite and universal character 
in every element of the skeleton in which the process normally 
takes place during intrauterine life. All the peculiarities which we 
have described in the specimen are referable to the perversion of 
ossification, and to this alone. 
In the examination of the long bones we found that complete 
sections were of great assistance, especially on comparing these with 
similar preparations of the normal nine months’ foetus. 
The large cartilaginous ends consisted of normal hyaline cartilage, 
actively growing, covered by perichondrium, and traversed by nume- 
rous large blood-vessels (see Plate III.). The short curved shafts 
consisted almost exclusively of periosteal bone ; the periosteum 
itself being actively engaged in ossification in the usual way ; the 
surface layer beneath the membrane is less compact than is usually 
the case. From the surface layer a regular system of trabeculae 
stretches right across the entire thickness of the shaft, to meet a 
similar series on the opposite side. Peripherally these trabeculae 
are closely approximated, and are for the most part parallel to each 
other. In the centre the spaces between the trabeculae are larger 
and more open, and are filled with marrow ; there is, however, an 
entire absence of anything in the shape of a medullary canal or 
endosteum. The process of excavation or hollowing out of the 
central core of the shaft, so evident in normal bones, is nowhere 
