HYDROCHLORIC ACID.— Hydro chloric acid is a clear, colorless, pun gent, fuming liquid having a strong acid odor and taste. It is miscible in all pro portions with alcohol and water. It is incompatible with the alkalies and their carbonates, and with the salts of lime, lead, and silver.
Preparations and ric acid, 5 to 10 minims (diluted).
I lydrochloric acid, dilute (10 per cent. acid), 10 to 30 minims.
Physiological Action. — In common with other mineral acids, hydrochloric acid in its pure form is a decided caustic and escharotic. Its great affinity for water and its combination with the alka line bases cause it to attack the living tissues energetically and induce destruc tive changes. Its caustic action is not as powerful or far-reaching as that of sul phuric or phosphoric acid. When in gested in a diluted form and in medic inal doses, its first action is to augment the salivary secretion. It is a general law that acids applied topically check the production of acid secretions from glands, while they increase the flow of alkaline secretions. Besides acting in this manner, the acid also acts through the cerebrospinal nerves supplying the gland (Ringer). On reaching the stom ach the acid combines with the alkaline bases present there and forms salts (by (Irochlorates), which are usually soluble and somewhat irritating. Hydrochloric acid is normally present (0.2 per cent.) as an ingredient of the gastric juice; it aids the pepsin to digest and render sol uble the albuminous and albuminoid converting them into peptones. It also aids in the transfor mation of pepsinogen into pepsin.
Hydrochloric acid has a very high dif fusive power and passes readily through animal membranes. Any portion of in gested acid which escapes union with the alkaline bases in the stomach diffuses rapidly into the blood and there forms salts with the bases of that fluid, setting free the weaker acids; this decreases the alkalinity of the blood and increases the acidity of the urine.
Action of combined hydrochloric acid on starch digestion. Conclusions: When a non-albuminous test-meal is given, free hydrochloric acid makes its appearance at the end of twenty minutes after eat ing, and at the end of half an hour the amount of free hydrochloric acid equals that of one or two hours after eating where albuminous foods are taken.
Under normal conditions, the ptyalin of saliva digests most of the starchy con stituents of food in the stomach within one or two hours. which takes place be fore free hydrochloric acid accumulates in the stomach to such an extent as to interfere temporarily with the diastasic action of saliva on starchy food. Those portions of starchy food which remain comparatively undissolved. and pass over to that portion of the digestive canal where they are acted upon by the pan creatic diastase, constitute a very small portion of the starchy food taken. The administration of isolated diastase con siderably enhances the digestion of starchy food in the stomach, even under normal conditions. The elimination of the supply of the ptyalin of saliva to the stomach will cause marked retardation of starch digestion in the stomach. A mal digestion of starchy food, to defi ciency of the diastasic power of saliva, can be regulated by the administration of isolated diastase. The impression held by many that the diastase of saliva be conies non-active fifteen or twenty min utes after eating is totally erroneous. A. E. Austin (Boston Med. and Surd. Jour., Apr. G, '99).
Poisoning by Hydrochloric Acid.— Hydrochloric acid is an irritant and cor rosive poison. When taken in a trated form it destroys the mucous brane of the mouth, epiglottis, cesopha gus, and stomach, and violent enteritis attended with very alarming symptoms ensues. Pain is present throughout the digestive tract; vomiting of coffee-ground matter, blood, or even portions of the mucous membrane is asso ciated with feeble pulse and clammy skin. Death occurs from collapse. Es chars are formed externally, and, al though the acid leaves a yellow stain on clothing, it does not stain the skin. If the case is seen very early, the character istic odor of the acid may be detected in the breath, and whitish pungent vapor may be seen issuing from the mouth.