tuberculosis is an acute febrile general disease which arises, in most cases, as a consequence of special hereditary predisposition. The dis ease expresses itself anatomically by the formation of the miliary nodule known as the gray granulation in the various organs of the body. This nodule is in great part an out-growth from the lymphatic system, and may be found wherever lymphatic or adenoid tissue normally exists. Acute tuberculosis is not to be confounded with pulmonary phthisis. Indeed, the two affections are essentially distinct, for ulceration of the lung, al though occasionally present, is by no means a necessary part of the tuber cular process.
In the young subject acute tuberculosis frequently assumes a form which is rare in the adult. In childhood the disease not uncommonly presents itself as a primary febrile affection, giving rise to but few symp toms, and those the manifestation merely of the general distress without any sign pointing to local mischief. It is often not until a few days be fore the close of the illness that any symptoms are discovered. to draw at tention to any particular organ. This is the primary form of the disease, which has much the character of an acute specific fever.
In other cases, almost at the same time with the beginning of the gen eral symptoms, others, more or less severe, are noticed, showing that some particular organ is especially fastened upon by the tubercular process. This form is not uncommon in cases of tubercular meningitis.
A third form resembles that which is often met with in the adult where the disease arises as a secondary affection in the course of some other ill ness, and in such a case brings the life of the child quickly to an end. This form is seen when tuberculosis supervenes upon empyema, pneumo nic phthisis, etc.
Acute tuberculosis attacks children of all ages, and may be seen in very young infants. When it occurs at this early age the anatomical feature of the disease is always very widely distributed. On the other hand, the older the child the more likely is it that the formation of the gray granu lation will be limited to special cavities of the body.
The word " tubercle " has been and is still employed in so vague a sense by various authors that it has almost ceased to convey any definite meaning. It may be well, therefore, to state that in the following pages the word is in every case used to signify the miliary nodule called "gray granulation " in the adult, but which in the child very quickly becomes yellow and opaque.
Causation.—Hereditary predisposition plays a very important part in the etiology of tuberculosis. In a large proportion of cases a distinct family tendency to the formation of tubercle can be discovered. The ten dencyis not, however, always exhibited in the parents. These are often, to all appearances, of sound constitution. It may be necessary to push our inquiries farther back and ask as to the health of the grandparents and of collateral branches of the family. In a child with this unfortunate predis position, any cause which impairs the nutrition of the body may excite the manifestations of the tubercular tendency. Therefore lowering complaints and insanitary conditions generally are justly regarded as important agents in the production of tuberculosis.
There are certain acute specific maladies with which the tubercular for mation is very apt to be associated. Whooping-cough and measles may be said to number tuberculosis amongst their sequeke, so common is it to find children convalescent from these complaints, who are placed under unfavourable conditions for complete recovery, fall victims to the disease. Typhoid fever is sometimes followed by it. Children who suffer from mal formation of the heart with narrowing of the pulmonary artery aro also very liable to become tubercular. They do not, however, often suffer from acute tuberculosis. In them the disease is more apt to assume primarily the form of chronic tubercular phthisis, even if the distribution of tuber cle become afterwards generalised. When the predisposition is strong, any cause which gives a shock to the system, such as a fall, a blow, or other similar accident, may be sufficient to excite the outbreak of the dis ease.