GROUP IV. SPONDYLITIS.
As already said, the cases with spinal involvement fall into two groups, one with general, the other with local involvement. The former is readily diagnosed, the latter is certainly much more easily overlooked. These cases are usually considered to belong to the "osteo- arthritic" group. The bony changes predominate, and especially new formation of bone. Certain writers hold that the osteoarthritic cases are quite distinct from the type previously spoken of as "rheumatoid" or those in which other than bony parts are especially involved. In certain of the cases of this series there seems no doubt of the occurrence of both types in the same patient. If this be true it goes far to prove that all the cases here grouped under the heading of arthritis deformane do belong to one disease which has various types. Not only were the two types of arthritis found in the