Many suppose that the diathesis, or a disposition to the diathesis, is always congenital; and this opinion is supported by the majority of cases. However, certain circumstances produce a scrofulous habit of body in patients who previously appeared to be vigorous and healthy, and untainted with any peculiar disposition to disease. Of these predisposing causes may be mentioned, a poor diet, an impure atmosphere, exposure to damp and cold, inattention to cleanliness, the latter circumstance acting sometimes by producing local irritation: in fact, whatever deranges the general health, seems, in many cases, to induce the strumous diathesis. Some constitutions are incapable of resisting any unusual incitement of the vascular system, or of repairing the consequences of the action, or of any injury, in whatever way inflicted. In such individuals, all the parts of the body are deficient in power—some, however, are more so than others, and, consequently, more readily give way; thus, the lymphatic system, the mucous membranes, the skin, the bones and their coverings, generally suffer in the first instance. Glandular swellings of all kinds, and in all situations, often followed by suppuration, are apt to occur from irritation of various descriptions, but more so in constitutions originally weak, or which have become debilitated by disease or any other cause. The larger glandular tumours are formed by congregation and agglutination of the smaller ones, and by the deposition of adventitious matter in the connecting cellular substance; separation of the smaller tumours composing these, naturally, or under the use of deobstruents exhibited internally, or applied to the surface, is a highly favourable sign, and equally encouraging to the surgeon and the patient. Dentition, the presence of carious teeth, of stumps of teeth; excoriations behind the ears, eruptions on the scalp, affections of the lining membranes of the eyelids, mouth, or nose, of the skin of the face, are daily found giving rise to glandular swellings in the neck; whilst irritations in the urethra, excoriation or slight disease about the anus, corns or sores about the feet or toes, produce similar affections of the glands in the groin. Such sources of irritation are, of course, to be looked for in the first instance, and will often materially influence the diagnosis, though too much is occasionally attributed to their influence. Such glandular tumours, however, sometimes occur spontaneously, or, at least, without any evident cause. They have been mistaken for other diseases, according to their situation—for aneurism, hernia, or venereal bubo; the latter mistake is often committed unintentionally by the ignorant, or designedly by the unprincipled.