The causes are all those which occasion debility generally, not excepting the most frequent of all, hereditary predisposition, that tendency to the disease which exists so strongly in some families that no care can ward it off nor prevent it seizing in succession member after member.
Consumption varies much in its initiatory stage: sometimes it steals upon the patient most slowly and imperceptibly; at others, it appears to start at once into activity. Generally, for a considerable period before marked symptoms show themselves, the person has felt weak, languid, and complained much of cold, probably has lost some flesh and a short dry cough has come on or there has been continued dyspepsia. If the patient is female, the monthly discharge has become irregular, or stopped. It may be that these symptoms have been aggravated during winter.
Such symptoms may go on for a longer or shorter period, ebbing and flowing, or they may progress more unremittingly, through still slowly, or become suddenly aggravated by some adventitious circumstance, such as cold taken.
The emaciation becomes too evident to escape notice, the cough is unabated and becomes troublesome, the voice assumes a hollow sound, the breathing is quickened, and it may be that spitting of blood, profuse night perspirations or even diarrhoea have set in before the patient's condition excites alarm in his own mind or that of his friends.
Taken from 'A Dictionary of Domestic Medicine and Surgery' by Dr S Thomson MD LRCS, and Dr J C Steele MD, published in 1882 by Charles Griffin and Co of London.