PHYSIOLOGY, CHEMISTRY AND PATHOLOGY 19 



ing action of pituitary extracts, the immediate results from intravenous 

 or hypodermic injections of pineal extracts are not pronounced. Such 

 phenomena as decrease in arterial tension, dilatation of the bloodvessels, 

 altered amplitude and rate of the heart beat, diuresis, glycosuria, and 

 uterine contractions have been reported and confirmed. 



Howell was the first to make mention of intravenous injections. In 

 1898j he administered pineal extracts as controls in experiments upon the 

 action of pituitary extracts. Apparently the results were such that no sig- 

 nificance was attached to the experiments. Von Cyon in 1903, using rab- 

 bits as subjects, made a study of the action of pineal extracts prepared 

 from ox and sheep glands. This worker reported that such extracts were 

 without definite effect upon the blood pressure. Following small doses, he 

 observed a tachycardia associated with a feeble pulse, which he attributed 

 to the presence of certain inorganic salts contained in the gland. At the 

 time of this publication, he concluded that the function of the pineal is 

 purely the mechanical one of controlling the flow of fluid through the 

 aqueduct. Dixon and Halliburton in 1909, in further experiments of this 

 type, employed extracts made up from a preparation of desiccated sheep 

 pineal glands. The dried glands were extracted with various solvents and 

 the extracts injected intravenously into cats. ~No mention is made as to 

 whether these glands were obtained from young or adult animals. Very 

 small doses were employed, and from these scant evidence was obtained 

 of any action. On using larger closes a transient fall of blood pressure 

 occurred, but no changes were reported to have occurred in heart rate or 

 amplitude, respiration, intestinal or kidney volume. In 1912, Ott and 

 Scott in several papers on internal secretion referred to experiments with 

 pineal gland extracts. Noteworthy are their observations that pineal 

 extracts induce vasodilatation in the erectile tissue of the generative organ 

 of the male cat, stimulate the contraction of the intestinal wall and uterus, 

 produce a slight diuresis and glycosuria and increase the activity of the 

 mammary gland. 



By far the most exact study of the immediate effects of pineal extracts 

 was made by Jordan and Eyster (1911). The material employed was 

 sheep's pineal glands, either freshly prepared or preserved in alcohol or 

 formaldehyd. The amount constituting a dose was usually the extract 

 from one gland given intravenously. Their own summary, here appended, 

 gives the scope of their work and their conclusions : 



"Our experiments indicate that the pineal gland of the sheep contains 

 some substance (or substances) which, on intravenous injection in cer- 

 tain animals, causes a fall of blood pressure associated with vasodilatation 

 in the intestines, produces a slight degree of improvement in the beat of 

 the isolated cat's heart, and causes a transitory diuresis associated with 

 glycosuria in about 80 per cent of the cases. We have found, in agree- 

 ment with Dixon and Halliburton, that the effect on blood pressure in the 



