What has been said with regard to complications and aftertreatment in the case of the male also applies to the female.

OTHER SURGICAL OPERATIONS.

Descriptions of other surgical operations not given in this chapter may be found in other parts of this work by reference to the index.

SURGICAL OPERATIONS.

DESCRIPTION OF PLATES.

Plate XXVI. Devices for casting cattle. (From Fleming.)

Fig. 1. Reuff's method of throwing or casting the ox.

Fig. 2. Miles's method of throwing or casting the ox.

Plate XXVII. Surgical instruments and sutures. (After Reynders and Fleming.)

Figs. 1 and 2. Seton needles. These may be either long or short, straight or curved, according to the locality in which a seton is to be inserted.

Fig. 3. Various forms of surgical needles.

Fig. 4. Suture forceps or needle holder, for pa.s.sing needles through thick and dense tissues.

Fig. 5. Knot properly tied.

Figs. 6, 7, 8, 9, 10. Various forms of sutures. Fig. 6, interrupted suture; 7, quilled suture; 8, uninterrupted suture; 9, twisted suture, made by pa.s.sing suture pins through the parts to be held together and winding the thread about them so as to represent the figure 8; 10, single-pin suture.

Fig. 11. Appliance for ringing the bull, one-fourth natural size.

Fig. 12. Nose clamp, with spring and keeper.

[Ill.u.s.tration: PLATE XXVI. DEVICES FOR CASTING CATTLE.]

[Ill.u.s.tration: PLATE XXVII. SURGICAL INSTRUMENTS AND SUTURES.]

TUMORS AFFECTING CATTLE.

By JOHN R. MOHLER, V. M. D.,

_Chief, Bureau of Animal Industry._

[_Synonyms:_ New growth, neoplasm, neoformation, pseudoplasm, swelling, and hyperplasia.]

_Definition._--Tumors[3] are abnormal ma.s.ses of tissue, noninflammatory and independent in character, arising, without obvious cause, from cells of preexistent tissue, possessing no physiologic function, and characteristically unrestrained in growth and structure.

Tumors are abnormal ma.s.ses of tissue. The application of the term "tumor"

is directly connected with the fact that they produce local enlargement.

They are noninflammatory; that is, the process of inflammation is not directly the cause or accompaniment of them. An inflammatory new growth tends to disappear upon the subsidence of the inflammatory process, while spontaneous disappearance of a tumor is comparatively rare.

Tumors are independent. For instance, their nutrition bears no relation to the nutrition of the body. A lipoma, or fatty tumor, in the subcutaneous tissue, may go on increasing to huge bulk while the body is steadily emaciating. Again, the tissues of the aged gradually undergo atrophy, yet cancers arise at this time and grow rapidly.

Tumors are unrestrained in growth and structure. In the development of an animal we know at what period of its existence the ma.s.s of tissue called liver will develop--what its site, structure, and size will be. We know that it will remain only in that locality, and not, as it were, colonize throughout the system. With tumors it is different; there are no laws by which we can forecast the time, place, nature, or size of development of them. There is no cartilage in the kidney or parotid gland, yet a chondroma, or cartilage tumor, may develop in either. Even when a new growth of tissue is started by an injury and consequent inflammation--as, for instance, proud flesh--there is a limitation of its size, but the controlling influences which govern the size of an organ or normal ma.s.s of tissue and limit the extent of an inflammatory overgrowth are all absent in the case of tumors. They are unrestrained, lawless.

Metastasis expresses the lawlessness of tumors as regards being limited to the original site of development. Small particles of tumors enter the blood vessels or lymph streams and are carried to distant parts of the body, where they lodge and start new tumor formations. Expansion by colonization in this manner is a rule with many tumors, and, since they exercise no function of use to the organism, this dissemination of actively growing particles becomes a menace to the system by numerically increasing the body's burden, opening new channels of drain upon the system and adding new centers for the absorption of putrefactive materials when the secondary tumors shall have degenerated. It is this which makes metastasis such an important element in the malignancy of tumors.

Tumors possess no physiological function. They are absolutely useless.

Fibrous tumors bind no parts of the organism together; bony tumors add nothing to the supporting framework of the body; the tissue of fatty tumors never serves as a storehouse of feed and energy; the cells of an adenoma, or gland tumor, furnish no secretion; a tumor composed of muscle tissue produces no increase to the strength of the individual--its muscle cells are not contractile.

Tumors arise from cells of preexistent tissue. Tumor tissue is not a new variety. Whatever the structure of a tumor, its counterpart is found among the tissues of the body, the lawlessness of the tumor, however, showing itself in more or less departure from the normal type. This departure is usually a reversion to a more elementary or embryonic stage, so that the tumor tissues may be said to be structurally immature.

Tumors arise without obvious cause. Concerning the ultimate cause of tumor formation we are absolutely ignorant. Various theories have been advanced from time to time, but none of them have been applicable to more than a limited number of cases. The most important theories may be briefly mentioned.

(1) _The theory of tumor diathesis._--Bilroth taught that tumors are caused by a peculiar predisposition consisting of a diseased state of the fluids of the body. This const.i.tutional taint might be acquired, but, having been acquired, is also hereditary. This theory is known also as the heredity hypothesis, but, while it is true that heredity appears to play some role in the causation of certain neoplasms, its application is too limited to make it of value.

(2) _The mechanical or irritant theory._--Virchow a.s.sumed that tumors arise as the result of previous irritation of the part. This has been noticed particularly in the case of certain cancers. They frequently develop on the edges of old ulcers, thus being dependent apparently on chronic irritation.

Cancer of the lip in pipe smokers is a case in point. Cancerous tumors of the skin often develop on the arms of workers in paraffin, tar, or soot, the chemical irritation of these substances being the cause. On the contrary, the proportion of those thus affected among the exposed is very small and forces the conclusion that if the real cause were in the irritation vastly more cases would occur.

(3) _The theory of nervous influence._--That is based upon (_a_) the observed fact that tumors occur more frequently in man and the higher animals than in those lower in the scale, among which the nervous system is less highly developed; (_b_) that certain formations seem to be directly connected with nerve distribution, while others have been a.s.sociated with alternations in neighboring nerve trunks.

(4) _The embryonal theory._--This is known also as Cohnheim's hypothesis.

In early fetal life there occurs a production of cells in excess of those required for the construction of the various parts of the body, so that a certain number of them are left over in the fully developed tissue or become misplaced during the sorting of cells for future development of tissues and organs. These cells lie dormant until favorable conditions arise or until some sufficient stimulus is applied, when, released from their inactivity, they begin to reproduce and grow. Not being normally related to their site, they lack the controlling and limiting influences of the part, and, their embryonic character enduing them with a most potent proliferating power, they develop in a lawless and unrestrained manner.

There are tumors whose existence can be explained only on these grounds.

Still, this theory falls far short of answering the question as to the origin of tumors.

(5) _The parasitic theory._--This is not only one of the latest, but, merely as a hypothesis, it is the most attractive and plausible of all. The serious objections to it, however, are the almost uniform failure that has met the attempts to transplant these tumors from one animal to another and the absence of any constant variety of organism in them. Several forms of parasites have been found in certain tumors, but nothing definite has been shown with reference to the relation they bear to the causation of the neoplasm.

CLa.s.sIFICATION OF TUMORS.

In Senn's work on tumors occurs the following: "A uniform system of cla.s.sification of tumors is one of the great wants of modern pathology, and all attempts in this direction have proved failures." It would be folly, therefore, to burden the pages of a work of this kind with one or several of the proposed systems which have, admittedly, at some important point, failed of their purpose. Since the value of this chapter depends chiefly upon its practical character, which in turn is measured by its aid in diagnosis, prognosis, and treatment, the old but important clinical division is here adopted.

Tumors are either malignant or benign. The essential difference between the two cla.s.ses is that while _benign tumors depend for their ill effects entirely upon their situation, malignant neoplasms wherever located inevitably destroy life._ The clinical features of each group are in many cases sufficiently marked to distinguish them.

MALIGNANT TUMORS.

(1) These are invariably pernicious, and from the beginning tend to destroy life.