SECRETION. 211 



the blood of a living animal have a remarkable influence upon the heart, 

 blood-vessels, and skeletal muscles. The contractions of the latteFHre pro- 

 longed, somewhat as after the action of veratriu. Upon the blood-vessels 

 the extracts cause a strong vascular contraction, giving an enormous increase 

 in blood-pressure, and upon the heart muscles also, if the vagus nerves have 

 been previously cut, there is a similar stimulating action manifested by an 

 increase in the strength and frequency of the beats. These effects are obtained 

 with very small doses of the extracts. Schaefer states that as little as 5J 

 milligrams of the dried gland may produce a maximal effect uppn a dog weigh- 

 ing 10 kilograms. The effects produced by such extracts are quite temporary 

 in character. In the course of a few minutes the blood -pressure returns to 

 normal, as also the heart-beat, showing that the substance has been destroyed 

 in some way in the body, although where or how this destruction occurs is not 

 known. According to Schaefer the kidneys and the adrenals themselves are 

 not responsible for this prompt elimination or destruction of the injurious 

 substance. It is possible that the substance in question may be continually 

 secreted under normal conditions by the adrenal bodies and play a very import- 

 ant part with reference to the functional activity of the muscular tissue. 



Pituitary Body. It is stated that complete removal of the pituitary body 

 causes death, accompanied by symptoms which resemble somewhat those fol- 

 lowing thyroidectomy, such as muscular tremors and spasms, apathy, etc. A 

 number of observers, therefore, have supposed that physiologically the pitui- 

 tary body is related to the thyroids, and is able to vicariously assume, to a 

 greater or less extent, the functions of the latter. The work upon this organ 

 has not, however, made sufficient progress to .enable any satisfactory statements 

 to be made concerning its possible functional value. 



Testis. Some of the earliest work upon the effect of the internal secretions 

 of the glands was done upon the reproductive glands, especially the testis, by 

 Browu-SSquard. 1 According to this observer extracts of the fresh testis when 

 injected under the skin or into the blood may have a remarkable influence 

 upon the nervous system. The general mental and physical vigor and espe- 

 cially the activity of the spinal centres are greatly improved, not only in cases 

 of general prostration and neurasthenia, but also in the case of the aged. 

 Brown-S6quard maintained that this general dynamogenic effect is due to 

 some unknown substance formed in the testis and subsequently passed into 

 the blood, although he admitted that some of the same substance may be 

 found in the external secretion of the testis, i. e. the spermatic liquid. More 

 recently Poehl 2 asserts that he has prepared a substance, spermin, to which he 

 gives the formula C 5 H 14 N 2 , which has a very beneficial effect upon the metab- 

 olism of the body. He believes that this spermin is the substance which 

 gives to the testicular extracts prepared by Browu-Sequard their stimulating 

 effect. He claims for this substance an extraordinary action as a physiologi- 

 cal tonic. The precise scientific value of the results of experiments with the 



1 See Archives de Physiologic normale et pathologique, 1889-92. 



2 See Zeitschrift fur klinische Medicin, 1894, Bd. 26, S. 133. 



