Thus the liability to tubercular infection is far commoner in the midst of a depraved population than in one fulfilling the primary laws of nature; rickets is a disease of great cities rather than of rural districts; and syphilis is more disastrous and protracted in its course in the depraved in health than in the robust.
In the lower jaw there are also one or two small and early deciduous premolars; third premolars of both jaws formed on the same type as that of the rat-kangaroos, but relatively much larger; molars rudimentary, tubercular.
Before the discovery of the bacillus of tubercle, scrofula and tuberculosis were regarded as two distinct diseases, and it was supposed that the scrofulous constitution could be distinguished from the tubercular.
A knowledge of the bacteriology of scrofulous affections of bone and joints, such as caries and gelatinous degeneration, has shown that they also are tubercular diseases - that is to say, diseases due to the presence locally of the tubercle bacillus.
General atrophy or emaciation is brought about by the tissues being entirely or partially deprived of nutriment, as in starvation, or in malignant, tubercular, and other diseases of the alimentary system which interfere with the proper ingestion, digestion or absorption of food material.