860 PROF. T. WINGATE TODD ON OSTEOMALACIA. 



Fig. 2. Right Ulna from same animal. Here and there are districts of gelatinous 

 fattj' marrow giving rise to lighter areas between the dark-coloured sites 

 of red marrow. The thickened periosteum and its intimate union with 

 the tissue composing the bone can be seen well, especially' near the centre 

 of the shaft. In this situation the bone was accidentally broken while 

 stripping off the muscles. 



Plate LXXXVIII. 



Fig. 3. Right Humerus of same animal. 



Note the irregular diaphj'so-epiphyseal junction at the upper end of the 

 shaft. The extreme brittleness of the bones resulted in the fracture of the 

 surgical neck of this humerus while the muscles were being removed. 

 There is no sharp line between the articular cartilage of the condyles and 

 the underlying spongy bone. This photograph shows clearly the articular 

 cartilage being destroyed on its bony aspect. 

 4. Right Tibia and Fibula from same case. 



Note extreme recurved upper portion of tibia. The bone had been fractured 

 some time previously' and had united in this position. The union is com- 

 plete. The fibula was likewise bent, its lower extremity is cut obliquely 

 and is shown behind the lower portion of the tibia. 



PlATE LXXXIX. 



Fig. 5. Longitudinal section of shaft of Left Ulna from the same animal. X40. 



Note the entire disappearance of Haversian systems from the bone and the 

 replacement of osseous tissue by fibrous material. The bony substance is 

 here shown broken up into islets. The section represents what once was 

 the compact bone layer of the shaft. 

 6. Longitudinal section of shaft of Left Ulna from the same animal. X206. 



A bone-islet is shown surrounded by non-osseous tissue. Note the gradual 

 transition of the bone into iibrous tissue. There is no sharp line of 

 demarcation, and no osteoclasts are to be observed. The decalcificatioii 

 progresses from the centre of the illustration to the periphery. Inter- 

 mediate between bone and fibrous tissue is a zone where the nuclei are 

 surrounded by considerable non-calcified protoplasm. This corresponds 

 in appearance to the pre-osseous stage in Retterer's description of 

 hone (5). 



