When the cancer is seated in other parts of the stomach and it does not obstruct the orifices, vomiting is more frequently absent or of only rare occurrence. Vomiting is absent, according to Lebert, in one-fifth, according to Brinton in about one-eighth, of the cases of gastric cancer. Absence of vomiting is sufficiently frequent in gastric cancer to guard one against excluding the diagnosis of this disease on this ground alone.
Although in many cases the vomiting of gastric cancer can be explained on mechanical grounds by stenosis of the orifices, this is an explanation not applicable to all cases. Mention has already been made of spasm of the oesophagus as a cause of regurgitation of food in some cases of cardiac cancer. A similar spasm of the muscle in the pyloric region may explain the vomiting in certain cases in which during life there were symptoms of pyloric stenosis, but after death no or slight stenosis can be found. There is reason also to believe that atony of the muscular coats of the stomach may cause stagnation of the contents of the stomach and dilatation of the organ. In exceptional cases of gastric cancer in which the stomach is so intolerant as to reject food almost immediately after its entrance a special irritability of the nerves of the stomach must be assumed. It is customary to refer this form of vomiting to irritation of the ulcerated surface of the cancer by analogy with a similar irritability of the stomach observed in some cases of simple gastric ulcer. But there is little analogy between the ulcerated surface of a cancer in which tissues of little vitality and irritability are exposed and the surface of a simple ulcer in which the normal or slightly altered tissues of the stomach are laid bare. Finally, in the existence of chronic catarrhal gastritis is to be found another cause of vomiting in many cases of gastric cancer.
The presence of fragments of the cancer in the contents removed by washing out the stomach with the stomach-tube has been observed by Rosenbach41 in three cases of gastric cancer, and utilized for diagnostic purposes. A cancerous structure could be made out in these fragments by the aid of the microscope. Hitherto, the presence of particles of the tumor in the vomited matter has been considered as hardly more than a curiosity, and I have not been able to find a well-authenticated instance in which such particles in the vomit have been recognized by microscopical examination. According to Rosenbach, the fragments of the tumor in the washings from the stomach can be recognized by the naked eye by the red, reddish-brown, or black specks on their surface, due to recent or old hemorrhages which have aided in the detachment of the fragments. By this means such particles are distinguished macroscopically from bits of food. By employing soft-rubber tubes and the syphon process there is no danger, in washing out of the stomach, of detaching pieces of the normal mucous membrane, which, moreover, can be distinguished from the fragments of the tumor by the aid of the microscope and usually by the naked eye. It remains to be seen how frequently such fragments of the tumor are to be found in the fluids obtained by washing out the stomach. It is not probable that they will be found so often as Rosenbach anticipates. According to the experience of most observers, they are very rarely present. They would naturally be most readily detached from soft, fungoid, and ulcerating cancerous growths. In this connection may also be mentioned the occasional separation of bits of the tumor by the passage of the stomach-tube in cases of cancer of the cardia. The eye of the tube as well as the washings from the stomach should be carefully examined for such particles.
41 Deutsche med. Wochenschr., 1882, p. 452.
The habitual absence of free hydrochloric acid in the gastric fluids in dilatation of the stomach due to carcinoma of this organ was noted by Von der Velden.42 He found in eight cases of dilatation due to cancer of the pylorus that the fluids removed by the stomach-pump were free from hydrochloric acid, whereas in ten cases of dilatation due to other causes, such as cicatrized simple ulcer of the pylorus, free hydrochloric acid was only temporarily absent from the gastric juice. Von der Velden therefore attributes to the presence or the absence of free hydrochloric acid in the gastric juice in these cases great diagnostic importance. The observations which have followed Von der Velden's publication are not yet sufficient to justify us in drawing positive conclusions in this matter. Recently, Kredel43 has reported from Riegel's clinic seventeen cases of simple dilatation in which free hydrochloric acid was only exceptionally and temporarily absent from the gastric fluids, and nineteen cases of cancerous dilatation in which, with very rare exceptions, free hydrochloric acid was continuously absent. Cases, however, have been observed by Ewald, Seeman, and others in which free hydrochloric acid has been found in stomachs dilated from gastric cancer. It is to be noted that free hydrochloric acid is absent from the stomach in other conditions than in gastrectasia due to cancer; of which conditions the most important are fever, amyloid degeneration of the stomach (Edinger), and some cases of gastric catarrh. Free hydrochloric acid is also usually absent during the first twenty minutes to an hour after a meal. We have not sufficient information as to the presence or absence of free hydrochloric acid in cases of gastric cancer without dilatation of the stomach. To Von der Velden's symptom no pathognomonic value can be attached, but it may prove, in connection with other symptoms, an aid in diagnosis. The presumption is against gastric cancer if free hydrochloric acid be found continuously in a dilated stomach. Less importance can be attached to the absence of free hydrochloric acid unless the observations extend over several weeks and fever and amyloid degeneration are excluded.
42 Deutsches Arch. f. klin. Med., Bd. 23, p. 369, 1879.
43 Zeitschrift f. klin. Med., Bd. 6, p. 592, 1884.
The tests for free hydrochloric acid are most satisfactorily applied to the fluids withdrawn by the stomach-pump. After a sufficient quantity for examination has been withdrawn the syphon process may be substituted. Tests may also be applied to vomited material, although here the admixture of secretions from the nose, mouth, and throat may render the results less conclusive. Edinger's method of swallowing bits of sponge enclosed in gelatin capsules and attached to a string, by which they can be withdrawn, may also be employed. The sponge should be free from sand, deprived of alkaline carbonates by hydrochloric acid, and rendered perfectly neutral by washing in distilled water.
For clinical purposes the most convenient tests are those which depend upon certain changes in color produced in reagents which enable us to distinguish inorganic from organic acids. In the gastric juice the only inorganic acid which comes into consideration is hydrochloric acid, and the most important organic acid is lactic.
1. Saturated aqueous solutions of tropæolin, marked in the trade OO (Von Miller, V. d. Velden). The solution should be perfectly clear and of a lemon-yellow color. This solution is colored red by the addition of hydrochloric acid even in very dilute solution (0.01 per cent.). A similar change in color is produced by lactic acid in somewhat less dilute solution (0.06 per cent.), but the red color produced by lactic acid disappears upon shaking with ether, while that produced by hydrochloric acid remains, unless the acid was present in very minute quantity. Tropæolin is therefore a very delicate test for free acid in general, but it does not distinguish so well as some other tests hydrochloric from lactic acid.