tumor, amputation should be performed as soon as evidences of a recurrence show themselves. Angioma of bone is an exceedingly rare affection, whereas myeloid sarcoma is common-facts which should not be forgotten in the differential diagnosis between these two affections of bone.

Intracranial Angiomata.-Demme has described blood-cysts of the superior longitudinal sinus that perforate the skull and appear externally as pulsating vascular tumors. A positive diagnosis between such . cysts and an extracranial plexiform angioma must be made before an operation is decided upon. Akidopeirasty with a fine needle will show whether or not the skull has been perforated. Intracranial angiomata may belong to blood-cysts of bone developed from the vasa nutritia of the parietal bone. As the walls of such cysts are lined by endothelial cells, the cysts are undoubtedly produced by angioblasts, possibly aided by mechanical causes. Other cysts communicating with the longitudinal sinus are multilocular. Bruns cites such a case. The cyst, which was discovered when the patient was fourteen years old, was situated in the parietal region and was composed of veins covered by normal skin. The cystic spaces communicated freely with one another. In a case of large plexiform angioma of the frontal region, the writer, in excising the tumor, found at its base large veins which communicated with the longitudinal sinus. The hemorrhage from this source could be controlled only by compression. Death resulted from suppurative sinus-phlebitis.

Angioma in the central nervous system occurs where the vessels are all new, all of them starting from the pia. Brunetti found such a tumor the size of a pea in the fourth ventricle. Klebs found a similar growth upon the surface of the middle lobe.

Liver. Cavernous angioma of the liver is of common occurrence. It appears in the form of round or wedge-shaped spaces filled with blood in parts of the organ not occupied by parenchyma. The spaces are nearly uniform in size. New spaces form in the fibrous septa and in the periphery of the tumor. It has been asserted that the cavernous spaces are formed by dilatation of pre-existing vessels accompanied by pressure-atrophy-an opinion which receives the sanction. of Ziegler. Such a view is untenable, as the structure of the tumor does not represent the conditions produced by vascular obstruction. The endothelial cells which line the spaces are attached to and supported by a strong scaffolding of connective tissue. In the neighborhood of such angiomata no evidences of inflammation can be found. Johannes Müller found in the lining of such spaces large spindle-shaped cells which are the endothelial cells. The number of these cells is not

the same in all parts of the wall: they are most numerous where the process of cell-proliferation is most active, and less numerous where the growth of the tumor has become stationary. Similar tumors are found less frequently in the spleen and the kidney.

Mammary Gland. In rare instances the mammary gland is the seat of an angioma. Sutton relates the case of a boy, seventeen years of age, who as a child had an ordinary nevus of small size in the skin above the left nipple. For many years this nevus gave no trouble; it then gradually increased in size until the whole breast was converted into a cavernous angioma three inches in diameter. At intervals the surface ulcerated, and profuse hemorrhages were the consequence. Another and larger angiomatous tumor of the breast came under the observation of Smage.

Tongue. The tongue is not infrequently the seat of simple and cavernous angioma. In a lad fifteen years old the writer successfully removed a tumor the size of a pullet's egg. The excision was greatly facilitated by elastic constriction of the affected side of the tongue.

Muscles. Cavernous angiomata of the voluntary muscles have been observed by a number of surgeons. In the clinic of Rush Medical College, Chicago, such a case came under the care of the writer during the session of 1894. The patient was a boy sixteen years of age. The tumor, which was first discovered five years previously, extended from a point three inches above the patella, over the outer aspect of the thigh, ten inches in an upward direction. The swelling was oblong, very prominent and firm when the patient was standing, but disappeared almost wholly when he was placed in the recumbent position with elevation of the affected limb. The tumor, which was removed. by excision, involved the outer part of the extensor quadratus femoris muscle, and extended on the outer side as far as the intermuscular septum. A strip of the muscle three inches wide and eight inches in length was removed, and on examination it was found to contain numerous vessels the size of a crow's quill. The hemorrhage upon the removal of the elastic constrictor was very profuse, and about fifty vessels had to be ligated before it was controlled. The boy made a good recovery and regained perfect use of the limb. The formation of a muscle-hernia was prevented by careful suturing of the fascia lata with a separate row of buried catgut sutures and rest in bed for six weeks.

Liston removed a cavernous angioma from the popliteal space in connection with the semimembranosus muscle. Holmes Coote removed a similar tumor from the deltoid, and Campbell de Morgan removed one from the semimembranosus in a girl ten years old.

In the diagnosis of muscular angiomata the variable size of the tumor in different positions of the body is an important element.

Larynx.-Except in the tongue and the rectum, angioma of the mucous membranes is very rare. It has been observed in the larynx in a few instances, springing from the vocal cords, the ventricular bands, from the ventricle, and from the sinus pyriformis. Angiomata of the larynx are either sessile or pedunculated. They are rarely larger than a haricot bean, and are red or purple in color. They should be removed with the snare, with the aid of the laryngoscope.

XXIV. LYMPHANGIOMA.

Definition.-A lymphangioma is a tumor composed of lymphatic vessels produced from a matrix of angioblasts. The lymphatic vessels. of the tumor are new structures containing lymph, and they constitute the essential part of the tumor. Their walls are more delicate than those of angioma, but they are composed of the same histological elements. A lymphangioma is a firmer tumor than an angioma, as the connective tissue between the vessels is more abundant.

Anatomical Varieties.-Wagner divides lymphangioma into-I. Capillary; 2. Cavernous; and 3. Cystic. In the capillary variety the tumor is composed of lymph-spaces and lymphatic vessels which constitute an anastomosing network. The cavernous variety is composed of a framework of connective tissue with communicating spaces which contain lymph. The cystic form presents to the naked eye an appearance of a convolution of large and small vesicles with translucent walls containing lymph. These vesicles are dilated new lymphatic vessels which have lost in part or completely their connection with the lymphatic system. Such cysts can be produced experimentally in rabbits by forcing atmospheric air under considerable pressure into the abdominal cavity. Under such conditions the air is forced into the lymph-spaces, especially those of the pelvis, producing rapid dilatation.

Histology and Histogenesis.-In capillary lymphangioma the new vessels are formed by angioblasts in the wall of pre-existing lymphspaces by a process of budding, in the same manner as in capillary angioma. As the vessels are composed of exceedingly delicate walls lined with endothelial cells, they dilate earlier and under less pressure than in angioma, consequently cystic dilatation takes place at an earlier period and to a greater extent. Capillary lymphangioma is always congenital, whereas the cavernous and cystic varieties may develop at any time after birth. The beginning of a capillary lymphangioma manifests more or less swelling before its lymphangiectatic character can be discerned. Microscopically, lymphangioma of the tongue, a comparatively frequent affection, appears in the form of a symmetrical swelling of the tongue, while the same affection of the skin begins in the subcutaneous connective tissue as a softer swelling with ill-defined borders. The loose connective tissue is oedematous, and

only in cases where large quantities of clear lymphatic fluid escapes can we suspect the existence of dilated vessels. In specimens that are somewhat finer, spaces can be seen traversing the tumor, while the delicate walls of the ectatic lymphatic vessels and cysts collapse so that the openings in the vessels cannot be seen. Microscopical examination, unless carefully conducted, may lead to errors in diagnosis, as the specimens often present more the appearance of hyperplasia of the tongue than that of dilated lymph-channels. In lymphangioma of the

FIG. 315.-Lymphangioma of the skin; X 375 (Surgical Clinic, Rush Medical College, Chicago): a, connective-tissue reticulum; b, round cells (lymphoid cells); c, lymph-space: d, blood-vessels.

tongue young muscle-fibres are met with, which proves that the muscular tissue is also increased in quantity. In the subcutaneous tissue the growth of lymphangioma is attended by an increase of connective tissue (Fig. 315).

The subcutaneous lymphangioma differs from elephantiasis arabum by the tumor being composed of new lymphatic channels instead of dilated diseased pre-existing vessels, as is the case in elephantiasis. Lymphangioma of the tongue (Fig. 316), or, as it is called, macroglossia, is always a congenital tumor. It commences with an enlargement of the blood-vessels; the veins are thin-walled, but a new tissue-product