“Any desired strength of secretin solution may be obtained according to the quantity of acid solution. In my experiments I used from ten to fourteen duodena to a pint of acid solution.”
“The solution of secretin prepared as above described is characterized by its ability to resist oxidation or deterioration for a sufficient period of time to render the solution available as a commercial article, and is furthermore characterized by freedom from poisonous and irritable chemical substances, whereby the secretin is chemically adapted to the human system to stimulate the pancreas to increased secretion.”
“As previously stated, the secretin prepared according to my method may be administered orally to produce the desired physiological action. Of course, if desired, the secretin might be injected intravenously, but this more or less dangerous procedure is not at all necessary, and I merely mention it here to point out that when I refer to the oral administration of my new secretin preparation, I do not mean to exclude its administration by injection.”
“As to the commercial stability of the secretin prepared according to my method, I may say that I have found by actual tests that the preparation maintains its stability for as long a period as five or six months. When I refer to my product as being “commercially stable,” I mean that it resists oxidation or deterioration for a sufficient period to render the same available as a commercial article. This period may vary from several weeks to several months, depending upon certain commercial factors well understood by the manufacturer. So, roughly speaking, I should say that secretin is commercially stable when it retains its activity from one to six months. I do not wish to be understood, however, as limiting myself to these exact figures.”
That active secretin may be extracted from macerated intestinal mucosa by weak acids below the temperature of boiling is well known. In fact, weak acids at body temperature in contact with the duodenal mucosa lead to the formation of secretin. The claims that secretin given by mouth reaches the blood and acts on the pancreas has been made for other preparations of secretin. It has also been shown that these claims are erroneous.[122] Thus it would appear that the only novel element in Dr. Beveridge’s patented secretin is the addition of serum, soluble proteins or peptones. What reason is there for believing that this will render the secretin stable for months, and physiologically active when taken by mouth? We do not believe Dr. Beveridge ever injected his secretin—protein mixture—intravenously in man or animals not under anesthesia, otherwise he would not have stated: “Of course, if desired, the secretin may be injected intravenously.”
BEVERIDGE’S PATENTED SECRETIN IS NOT STABLE
I. The Samples of Secretin Sent Us by Dr. Beveridge.—Physiological tests were made on four quart bottles of the secretin kindly sent us by Dr. Beveridge June 26, 1916. According to a letter from Dr. Beveridge of July 20, 1916, those samples of secretin were prepared June 20, that is, only six days before received by us. The material came in dark colored bottles. It was kept in the original bottles and placed in the ice box immediately on receipt. Dr. Beveridge stated the secretin “should remain active until the month of November, 1916, at least.”
Tests were made on three out of the four bottles. The fourth bottle was not opened, as we desired to learn what change it might undergo in the way of protein precipitation and bacterial decomposition. There is nothing in the Beveridge method of preparation that insures a sterile secretin unless it is passed through a Berkefeld filter. In all our crucial experiments the animals (dogs) were kept under light ether anesthesia, a cannula inserted into the pancreatic duct, the blood pressure recorded from the carotid artery and the various secretin preparations injected intravenously. When inactive secretin preparations were encountered, control tests were always made with active solutions of secretin to eliminate possible individual peculiarities of the animal. Thus when the pancreas of a dog reacts to the injection of preparation A, but not to preparation B, it is evident that absence of response to B is due to this preparation and not to the animal or to the experimental conditions.
Fig. 1.—Records of carotid blood pressure and secretion of pancreatic juice on intravenous injection of Beveridge’s secretin in dogs. X, injection of 10 c.c. secretin; b, record of flow of pancreatic juice in drops. Tracing A, injection of 10 c.c. of one sample secretin (ten days old) furnished by Dr. Beveridge. Tracing B, injection of 10 c.c. of second sample of secretin (ten days old) furnished by Dr. Beveridge. Tracing C, injection of 10 c.c. of secretin (twenty hours old) made by us according to the Beveridge method. Showing that the secretin preparations sent us by Dr. Beveridge contained no secretin.