It is necessary, therefore, for the singer to study himself, to learn by experience what is good and what is bad for him. This is a matter in which individual peculiarities play so great a part that only very general rules can safely be laid down. Singing within less than two hours after the eating of a hearty meal is almost certain to have an injurious effect on the voice. Exposure and over-fatigue must be carefully avoided. Stimulants, especially alcohol and tobacco, have a markedly bad influence on the mucous membranes of the throat. But beyond general statements of this kind, so obvious indeed that their truth is fairly well known, little can with safety be said as to the regimen imposed on the singer. That one man’s meat is another man’s poison is most strikingly true in its application to the voice. Many famous singers have been excessive smokers without seeming to suffer any ill results from the habit. Yet with most vocalists tobacco has a very irritating effect on the mucous membranes. So, also, with regard to eating and drinking, the widest differences of individual constitution are seen. Hot drinks are beneficial to some voices, injurious to others; cold drinks and ices are equally contradictory in their influence on the voice. All these questions of daily habit must be decided by each singer for himself and experience is the only safe guide. There is a class of dangers to which the voice is exposed, entirely distinct from the influence of unfavorable conditions of the general health. Most of the throat troubles to which singers and public speakers are liable are directly traceable to a wrong use of the vocal organs. One of the most striking facts regarding the voice is this: If the voice is correctly produced it is benefited by exercise and improves steadily, year after year, in power, beauty, and facility of execution. On the other hand, when the voice is wrongly or imperfectly used exercise has exactly the opposite effect. Badly produced voices constantly deteriorate; their use results in course of time in throat troubles, of which the number and variety seem almost inconceivably great.