toneal glands in the inguinal region contraindicates castration. Some of the sarcomatous tumors of the testicle contain striated muscular fibres, and in very rare cases the tumor is pigmented.

Brain and its Envelopes.-In the brain we have described, as peculiar varieties of sarcoma, psammoma and glioma. The dura mater is not infrequently the starting-point of sarcoma. The tumor destroys the bone over it, and appears, after perforation has taken place, as a pulsating tumor.

Operative treatment is contraindicated in psammoma and is of doubtful propriety in glioma. Bergmann for good reasons opposes intracranial operation for malignant disease. Surgeons, however, will continue to operate for glioma, as the tumor frequently produces focal symptoms which enable them to locate it with precision, and a positive diagnosis is usually made only after the tumor has been exposed or after operation, by examination of sections of the tumor under the microscope.

Sarcoma of the dura mater, if it could be diagnosed at an early stage, should be removed by operation. After the tumor has perforated the skull the intracranial part of the tumor is usually so extensive that an operation would prove of no avail.

Eye. The optic nerve and its branches are not infrequently the seat of glioma. In the interior of the eye the malignant tumors are represented by melano-carcinoma and melano-sarcoma, the latter being much the more frequent. Pigmented sarcoma may arise from any part of the uveal tract—that is, from the pigmented tissue of the iris, the ciliary body, and the choroid. The commonest seat is the choroid.

The intraocular sarcomata are either round-celled, spindle-celled, or mixed-cell sarcoma. Sarcoma of the eye occurs most frequently in persons from forty to sixty years of age, but is occasionally seen in children. The tumor extends along the blood-vessels and the optic nerve. The increased intraocular tension results in sloughing of the cornea, when the tumor protrudes in the form of a pigmented fungous mass. Extension of the tumor along the optic nerve into the cranial cavity does not often take place. Metastasis at quite an early stage is of frequent occurrence, the tumor in this respect resembling melano-sarcoma of the skin.

Early enucleation is the only surgical resource in all cases of melanosarcoma of the interior of the eye. This operation should be performed as soon as the tumor can be detected and diagnosed by the aid of the ophthalmoscope.

Bladder.-Sarcoma is a very rare affection of the bladder, and most of the cases so far reported were in young fees. Küster

reported five cases, and one case came under the observation of König, who removed a pedunculated round-celled sarcoma the size of a hen's egg from the neck of the bladder by perineal section. Sarcoma in the bladder, in its structure and its manner of local extension, very closely resembles sarcoma of the uterus. It starts most frequently in the submucous connective tissue. In the differential diagnosis between sarcoma and carcinoma of the bladder it is important to remember that sarcoma is much the more rare, that it is found in preference in young females, and that ulceration occurs later than in sarcoma. differential diagnosis between sarcoma of the bladder and benign tumors, and the treatment, are the same as in carcinoma.

The

Prostate. Malignant tumors of the prostate start primarily in this organ, as the prostate is seldom affected secondarily either by extension of the tumor from an adjacent organ or by metastasis. Wyss collected 28 cases of malignant disease of the prostate in young boys less than ten years old. In all of the cases the prostate was the primary seat of the tumor. The symptoms resemble those of carcinoma of the same organ. Thompson has reported 18 cases of primary malignant tumors of the prostate. Kapuste has shown by his investigations that tumors of the prostate in children are usually sarcomatous, while carcinoma of this organ is a disease of advanced age. Besides the functional disturbances produced by the tumor, spontaneous pain, hemorrhages, and the escape of fragments of the tumor after ulceration has set in are the most conspicuous clinical phenomena.

Radical operations for tumors of the prostate have been performed by Billroth, Demarquay, Nussbaum, and others. In Nussbaum's and Billroth's cases a part of the rectum was removed with the prostate and a part of the bladder-wall. If the disease has not extended beyond the prostate-and these are the cases to which radical operations should be restricted-the prostate and as much of the neck of the bladder as is endangered by the tumor should be removed through the perineal incision devised by Zuckerkandl. The efficiency and safety of the operation would be enhanced by a preliminary suprapubic cystotomy.

XXIX. TERATOMA.

So far we have considered tumors composed of a single representative histological element. We have studied tumors composed of cells derived from one of the germinal layers-the epiblast, the hypoblast, and the mesoblast-and have found that the different classes of tumors represented the tissues of only one of these embryonal layers. The epiblast and the hypoblast were represented by papilloma, adenoma, and carcinoma; the mesoblast, by the different tumors representing the connective-tissue type of benign tumors and sarcoma. We now come to the last class of tumors that contain tissues and organs derived from two or all of the germinal layers.

Definition. A teratoma is a tumor composed of various tissues, organs, or systems of organs which do not normally exist at the place where the tumor grows. The highest type of a teratoma is a fœtus in fœtu. In the simpler varieties the tumor is composed of heterotopic tissues, such as bone, teeth, skin, mucous membrane, etc. All teratoid tumors are congenital; that is, the tumor either exists at the time of birth or the patient is born with the essential tumor-matrix. A teratoma never springs from a matrix of post-natal origin.

Origin of Teratoid Tumors.-A tumor composed of a single representative histological element frequently starts from a matrix of postnatal origin, as the writer has aimed to show in connection with all the tumors so far discussed; but the more complicated matrix of a teratoma has invariably a congenital origin, and is produced in the embryo by errors of growth and by displacement of tissue by inclusion. Klebs classifies teratoma according to their origin into endogenous and ectogenous, the former arising from a matrix formed in the same individual, the latter from foetal inclusion. The latter mode of origin is possible, but certainly very rare. A case of this kind was recently reported from Gussenbauer's clinic by Pupovac. The patient was an infant, and the congenital tumor involved the side of the neck. Examination of the tumor showed embryonic tissue representing different parts of the body-bone, cartilage, muscle-, gland-, and brain-tissue. One of the strongest arguments in support of the correctness of Cohnheim's theory concerning the origin of tumors is furnished by the teratomata. Maas succeeded in producing dermoid cysts artificially in animals by implan

tation of dermoid fetal tissue. He produced dermoid cysts in young rats by introducing into the peritoneal cavity pieces of skin and parts of limbs of new-born rats. After two and a half months he found small cysts containing pus, cholesterin, and hair. The lining of these cysts was composed of tissues representing all the histological elements of true skin.

A great deal of speculation has been rife in reference to the origin of the higher types of teratoma. Rauber pointed out that two embryos may spring up in union in the same blastoderm or close to one another, in which case they may afterward fuse. Fusion is more frequent at the caudal extremity, but occasionally it occurs at the cephalic end or elsewhere along the vertebral axis. In the subsequent growth the embryos usually develop unequally until one becomes a mere parasite on the other. In conformity with this explanation is the fact that dermoid teratoid formations in the region of the coccyx are proportionately common. At the cephalic end, in the region of the hypophysis, teratoid tumors are occasionally met with, the origin of which could be explained upon the same hypothesis. Williams, on the contrary, is firmly convinced that such tumors are produced not by blending of two distinct embryos, but by giant growth of undifferentiated cells; "Occasionally a mass of undifferentiated protoplasmic cells manifests reproductive properties similar to those of the hydra, so that from a single cell two or more individuals may proceed. Thus, when the division of the undifferentiated embryo into two symmetrical parts is complete, and each of these develops into a new being, homologous twins are the result; and this, so common a mode of reproduction in the lower animals and plants, is the only instance of reproduction by gemmation in the highest animals. In this way double monsters arise. The locality and degree of fusion present many variations. The usual points of attachment are the sacrum, sternum, umbilicus, and head. The sex of the individuals in homologous twins and double monsters is invariably the same. In other instances the distribution of protoplasmic cells in the embryo is unequal, so that only one of the two fetuses attains full development. The former are called 'autosites;' the latter, parasites,' because they depend for nutrition upon the body to which they are attached. The parasite is either attached to the surface of the autosite by implantation or is surrounded by the tissues of the autosite by inclusion. Sometimes only a part of a new individual is formed in such a manner, which gives rise to tumor-like formations called by Virchow 'teratoma.' Such tumors are found most frequently in the region of the ovaries, testicles, sacrum, and sella turcica. They represent imperfect parasitic fetuses. Partial fission of the embryo at the cephalic end gives rise, according to the degree of fission, to

duplication of the pituitary body, to the formation of two distinct and complete faces. Additional masses of protoplasmic cells result in the formation of all kinds of deformities, as supernumerary fingers and toes, supernumerary mammary and thyroid glands, and, if the cells only possess the intrinsic capacity to produce one tissue, all conceivable forms of local hypertrophies, such as angiomas, moles, warts, lipomas, etc."

There can be but little doubt that double monstrosities are the result of fusion of two distinct embryos, as symmetrical segmentations of an embryo to this extent in man and the higher animals is not likely to occur. We have also reason to believe that ectogenous and endogenous parasites originate in a similar manner, while the different varieties of dermoids, the teratomata proper, originate in the manner indicated by Williams and others.

Endogenous Teratomata.-These tumors are represented by the histioid and organoid varieties. The histioid variety is represented by heterotopic tumors, such as chondroma branchiogenes, branchial cysts, and the simplest forms of dermoid cysts. The organoid tumors spring from displaced embryonal matrices representing different tissues and organs, and occur in localities where in the embryo displacement of tissue has taken place. The capacity of tissue-proliferation of the cells of which the matrix is composed does not exceed that of the cells of the corresponding normal tissue. For instance, a dislocated toothgerm will produce a tooth not larger than a normal tooth, and a dislocated acinus of a gland will produce an acinus which in size does not exceed the acinus of a corresponding normal gland.

Sutton describes a rare case of ovarian mamma removed from a woman twenty-six years of age, supposed to be suffering from tubercular peritonitis. Upon opening the abdomen a considerable quantity of pus escaped, mixed with hair and sebaceous material, showing it to be the remains of a dermoid cyst. On examination, a peculiar, rounded body, growing from the wall of the cyst, was found, recognized as an ovarian mamma, and removed. It presented an ordinary nipple and a cluster of glandular material, the ducts of which traversed the nipple. The endogenous skin-teratoma is the most frequent form of fetal inclusion. Portions of the embryonal skin become buried in the mesoblast and are isolated by constriction from the skin, and serve later as matrices for dermoid tumors. In many endogenous teratoid tumors. the matrix, derived in a similar manner, has a more complicated structure, and from it develop teeth, bone, portions of the alimentary canal, etc. In such a manner originate, in the interior of the skull, tumors containing striated muscular fibres (Arnold) and teeth (Hugo Beck).

Ectogenous Teratomata.-Ectogenous teratomata are produced by