218 DISEASES OF THE JOINTS. 



within the cartilage corpuscles. Another change is the infiltra- 

 tion of the cartilage with the salts of lime, this change com- 

 mencing in the cell wall. This may often be seen in the 

 cartilage of the navicular bone. The alteration in the hyaline 

 substance consists in its losing its glistening appearance, and 

 being split up into shreds of fibres projecting into the joint. 



Dr. Eedfern has arrived at the following conclusions from his 

 inquiries into this subject : — • 



1st. That all the known forms of disease in articular cartilage 

 are connected w^ith changes in the texture, which are essentially 

 similar to each other. 



2d. That during the progress of these changes the cells of the 

 cartilage become enlarged, rounded, and filled with corpuscles, 

 in lieu of healthy cells ; bursting subsequently, and discharging 

 tlie contents into the texture on the surface ; whilst the hyaline 

 substance splits into bands and fibres, and the changed hyaline 

 substance, and the discharged corpuscles of the cells afterwards 

 form, in many cases, a fibro-nucleated membrane on the surface 

 of the diseased cartilage. 



3d. That these changes are referable only to an abnormal 

 nutrition as their immediate cause, and in no case to mechanical 

 or chemical actions, such as attrition, or digestion in a diseased 

 secretion. 



Ath. That most extensive disease may go on in many joints at 

 the same time, and may proceed to destroy the whole thickness 

 of the cartilage in particular parts, without the patient's know- 

 ledge, and while he is engaged in active occupation. 



5th. That the disease commences most frequently on the free 

 surface, but may proceed from the bone to affect the attached 

 surface, or may take place in the middle of the thickness of the 

 cartilage. 



6th. That it is at least very doubtful if the symptoms whicli 

 are believed to indicate the existence of ulceration of articular 

 cartilages are not really dependent on a morbid change in the 

 bone. 



7th. That disease of the whole thickness of an articular carti- 

 lage at particular parts admits of a natural cure, by the formation 

 of a fibro-nucleated membrane from the substance of the cartilage, 

 without the occurrence of any new exudation. 



When cartilage is destroyed, it is never reproduced. If the 



