The explanation for the innate relationship between the poison of congenital syphilis and the fatal osseous system is to be found in the powerful and peculiar method of growth of the skeleton, which has this peculiarily, that it grows, not uniformly, but by apposition either through inetaplasia of cartilage or through increase from the periosteum. Those portions of the bony system in which growth is most active are the ones that most attract the poison of syphilis circulating in the foetal organism, and so there arises in foetuses and young infants that affinity for the epiphyseal borders of the long hollow bones and for the tuberosities of the cranial bones. In this so - called osteochondritis heredosyphil itica of Wegner the most prominent changes that are found are disturbances in the metaplasia of the car tilaginous ground substance about the intrachondral medullary spaces, abnormal proliferations of car ti 1 age cells, necrotic processes within the cartilage, intra chondral cleft formation, and pathological calcification.
In the zone of the subehondral medullary space formation there occur at first hyperaemic inflammatory processes with simultaneous transformation of the marrow of the spongy portion into granulation tissue and the failure of osteoblast formation. Frequently before this time changes in the consistency of the marrow have appeared at the diaphyseal ends with retrogression of vascularization. The marrow at the cartilaginous borders often becomes transformed into fibrous con nective tissue.
The disturbances of periosteal and perichondral ossification con sist at first of subperiosteal envelopment of granulation tissue, from which results a melting, as it were, of the compact bony substances. Through calcification of this granulation tissue there arises abnormal hyperostosis, often even the formation of many layers about the pri mary bone which is embedded in the new shell of bone, like the end of a cigarette in its holder. Besides this ossifying periostitis there is also a chondrifying periostitis in the region of the epiphyseal borders, if within these there is taking place, or has taken place, a break in continuity. Under these conditions there can occur, just as in real fractures, the formation of genuine callus, at first cartilaginous, later bony.
According to Wegner (1S70) three stages of osteochondritis can be distinguished. In the first stage the zone of calcification of the car tilage is broadened and irregular, distinguished from the bluish shim mering cartilage and from the strongly hypertemic spongiosa by its greater density and lighter color. The second stage is characterized by
the establishment of a broad mortar-like layer belonging to the pro visional zone of calcification between the epiphyseal cartilage and the diaphysis. In the third stage there follows in connection with the hyaline cartilage toward the diaphyses a wholly irregularly defined layer several millimetres wide of a grayish yellow mortar-like mass which is very compact (broadened, irregular calcification of cartilage). Next to this is a grayish yellow or grayish red layer of varying width and of light density, that gradually disappears as the spongiosa is approached. On account of this mass of slight resistance the natural connection be tween epiphysis and diaphysis is disturbed, frequently to such an extent that the shaft of the bone remains attached to the epiphysis only through the thickened periosteum.
The beginning stages of osteochondritis are usually not recogniz ble macroscopically, but can be demonstrated microscopically.
With reference to the anatomical conditions in separation of the epiphyses in hereditary syphilis, one must remember that this is essen tially a fracture which takes place either in the subehondral granulation tissue, or, if necrotic processes exist, in the columnar portion of the cartilage. Lessening of density, trauma, and muscular action, are the causal factors. For this reason epiphyseal separation in hereditary syphilis occurs only in the long hollow bones, never in the ribs, or short hollow bones.
The short hollow bones show intrachondral and periosteal patho logical processes that are quite similar to those found in the long bones.
There are disturbances in the endochondral ossification and rarifying diaphyseal processes. and also characteristic periosteal affections. ration of the epiphyses and involvement of the small joints are never found. Joint affections are very rare in hereditary syphilis during the first year, but they do occur during the second year, especially in the larger extremities, but only rarely in those connected with the bral column. Joint suppuration in syphilitic infants is always the result of mixed infection. The confounding of gonorrhceal and pyfrinic joint inflammations with osteochondritis of congenitally syphilitic origin has doubtless occurred many times, especially since the extremities are found in positions that suggest paralysis in all of these conditions.