This section is from the book "A Treatise On Therapeutics, And Pharmacology Or Materia Medica Vol1", by George B. Wood. Also available from Amazon: Part 1 and Part 2.
Medicines are applied to the two opposite extremities of the alimentary canal; to the stomach, namely, and to the rectum.
This is the most convenient, generally the most effective, and by far the most frequently employed avenue for medicines into the system. To this, as to any other part, they may be applied with the view exclusively to a local effect; but much more frequently the object is to act on the system at large, or on some distant part, for which the stomach affords great facilities, both by the readiness with which absorption takes place from its inner surface, and the sympathies which connect it, beyond any other accessible organ, with all parts of the body. The forms in which medicines are introduced into the stomach have been already referred to. The modes of administering them are in general too obvious to require notice. Two or three remarks, however. upon this point will not be irrelevant. 1. Sometimes patients are comatose, and cannot voluntarily swallow medicines. In these eases, there sometimes danger of the medicine passing into the glottis, and producing embarrassment of respiration. Substances, however, which act in small doses, as croton oil, may be placed upon the tongue towards its further extremity, where they excite the reflex action of deglutition, and are often swallowed. 2. Children not unfrequently refuse to take medicine into their mouth, and cannot be prevailed on by any persuasion. They can generally be made to swallow, without great difficulty, by taking them in the lap, closing the nostrils so as to compel them to open the mouth, and then introducing the medicine by a teaspoon. 3. In the cases of adults who, from insanity or the purpose of suicide, will not, or from paralysis or insensibility, cannot take medicine, the physician may sometimes be justified, in order to save life, in forcibly injecting it into the stomach by means of the stomach-tube and a syringe.
Attempts have been made, in cases of impervious and incurable stricture of the oesophagus, to prevent starvation by making a fistulous opening from without into the stomach, through which food might be introduced; but the experiment, though not without some encouraging circumstances, has not hitherto proved successful. Considering that, in several instances, such openings have resulted from accidental wounds, and the patient afterwards recovered, with a permanent fistulous orifice, or even an aperture of considerable size, the operation of gastrotomy would seem to be justifiable in otherwise necessarily fatal cases. (See Guy's Hospital Reports, iv. 1).