Finally most investigators have made their inquiries for the exclusive purpose of discovering the evil effects of tobacco smoking. They proceed to their work with a biassed mind. They have already assumed that the habit is harmful and they simply want to find out how much harm they can discover. They are prejudiced from the beginning. It is to this class of investigator that Dr. John Aikman refers to (New York _Medical Journal_, Oct. 30, 1915), when he says: "In reading the literature on the use of tobacco we are impressed by the fact that much of it is written by persons greatly opposed to the use of the plant, and naturally prejudiced." It is quite conceivable that a man may investigate the evil effects which follow from wearing clothes and shoes and he could undoubtedly find some evil effects; but the users of such articles could very justly say that the beneficial results of such habits more than outweighed the demonstrated harm that might occur. And then the user of tobacco might say that the beneficial effects of smoking more than compensated for any slight harm that may happen. For tobacco has undoubtedly many excellent effects, and no one knows this better than the smoker himself. He will readily admit that excess is bad. He will readily admit that the use of tobacco is not suitable to immature persons, or in fact to many other persons, but he insist that in the majority of cases, it is not only practically harmless but that it has many desirable qualities, for that is proved by his own experience and the experience of millions of other smokers in all ages and under all conditions. We will now proceed to consider some of the effects which have been ascribed to tobacco smoking and give expressed opinions concerning them. PHYSICAL EFFECTS OF TOBACCO SMOKING The principal deleterious effects on the human system ascribed to the use of tobacco are: (a) Throat diseases. (b) Disturbance of vision. (c) Heart troubles (smokers' heart). (d) Disturbance of the digestive organs (dyspepsia, etc.). (e) Disturbance of the nervous system. (f) Disturbance of nutrition. As regards (a) throat diseases, the following is the opinion of Dr. H. Reik of the Johns Hopkins University, surgeon to the Baltimore Eye, Ear and Throat Hospital, as expressed by him in the Boston _Medical and Surgical Journal_, Vol. 162, p. 856, 1910: "There is not one scintilla of evidence that malignant disease of the throat is due in any way to the use of tobacco; and if it be admitted that carcinoma (cancer) of the lip or tongue has been produced by smoking, it is clearly _not tobacco_, but traumatism (i. e., injury) from the stems of the pipe or other tobacco container that is responsible. "It does not appear or at least has not been proven that tobacco causes any definite characteristic lesions of the nose, throat or ear."