is_.

The lesions met with later correspond to those of the tertiary period of
the acquired disease, but as they affect bones which are still actively
growing, the effects are more striking. Gummatous disease may come and
go over periods of many years, with the result that the external
appearance and architectural arrangement of a long bone come to be
profoundly altered. In the tibia, for example, the shaft is bowed
forward in a gentle curve, which is compared to the curve of a
sabre--"sabre-blade" deformity (Fig. 132). The diffuse thickening all
round the bone obscures the sharp margins so that the bone becomes
circular in section and the anterior and mesial edges are blunted, and
the comparison to a cucumber is deserved. In some cases the tibia is
actually increased in length as well as in girth.

[Illustration: FIG. 132.--Sabre-blade Deformity of Left Tibia in
Inherited Syphilis.

(From a photograph lent by Sir George T. Beatson.)]

The contrast between the grossly enlarged and misshapen tibia and the
normal or even attenuated fibula is a striking one.

_Treatment_ is carried out on lines similar to those recommended in the
acquired disease. When curving of the tibia causes disability in
walking, the bone may be straightened by a cuneiform resection.

_Syphilitic dactylitis_ is met with chiefly in children. It may affect
any of the fingers or toes, but is commonest in the first phalanx of the
index-finger or of the thumb. Several fingers may be attacked at the
same time or in succession. The lesion consists in a gummatous
infiltration of the soft parts surrounding the phalanx, or a gummatous
osteomyelitis, but there is practically no tendency to break down and
discharge, or to the formation of a sequestrum as is so common in
tuberculous dactylitis.

The finger becomes the seat of a swelling, which is more evident on the
dorsal aspect, and, according to the distribution and extent of the
disease, it is acorn-shaped, fusiform, or cylindrical. It is firm and
elastic, and usually painless. The movements are impaired, especially if
the joints are involved. In its early stages the disease is amenable to
anti-syphilitic treatment, and complete recovery is the rule.

HYDATID DISEASE

This rare disease results from the lodgment of the embryos of the taenia
echinoccus, which are conveyed to the marrow by the blood-stream. The
cysts are small, usually about the size of a pin-head, and they are
present in enormous n