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.
The most important disease hitherto undescribed was rickets, first made known by Arnold de Boot, a Frisian who practised in Ireland, in 1649, and afterwards more fully in the celebrated work of Francis Glisson (1597-1677) in 1651.
Rickets, scurvy and "marasmus" may be instanced as diet diseases in children.
He published at Oxford in 1668 two tracts, on respiration and rickets, and in 1674 these were reprinted, the former in an enlarged and corrected form, with three others "De sal-nitro et spiritu nitro - aereo," "De respiratione foetus in utero et ovo," and "De motu musculari et spiritibus animalibus" as Tractatus quinque medico-physici.
Owing to this influence it has been used in rickets and osteomalacia.