A new method of testing the acidity of the stomach contents has been devised by E. K. Dunham.1 It consists in having the patient swallow a thread colored with litmus, congo, or dimethyl-amido-azo-benzol.

Thirty inches of thread, with a small tassel attached to the end, can be swallowed with from 10 to 30 c.c. of water; a quantity too small to greatly dilute the contents of the stomach, and probably not sufficient to materially modify qualitative tests.

The apparatus required is very simple; a thread, preferably of silk, a cylindrical reel of wood about half an inch in diameter, a glass tube of small calibre, and a small tassel of test threads colored with the desired indicators. The tassel is tied to one end of the thread, which is about thirty inches long. The free end of the thread is then passed through the glass tube, tied to and then wound upon the reel, the tassel being made to just engage in the opening of the tube. This reel is then floated upon water in a glass, the tassel end of the tube placed well over the arch of the tongue, and the water drunk through the tube in small, quick swallows. The end of the tube which dips into the water should be kept well below the level of the reel, otherwise the thread, in passing into the tube, will draw the reel against the end of the tube and cause too much friction.

1E. K. Dunham: "A Thread Test of the Acidity of the Stomach Contents." The New York University Bulletin of the Medical Sciences, vol. i., No. 4. p. 178, October, 1901.

When the act of swallowing has unwound all the thread on the reel, the free end is detached from the reel and the tube removed from the mouth. The thread should not be withdrawn from the stomach in less than three minutes, and it is better to let it remain there for five minutes. After removal, it should not be washed lest the original color return to the threads dyed with dimethyl-amido-azo-benzol.