242 FRANK A. HARTMAN 



the fact that the anesthetic employed frequently maintains the bronchioles 

 in a more or less dilated condition. Then if epinephrin produces any 

 effect it is most often constriction. The evidence at present appears to 

 favor the view that this substance will produce dilatation of constricted 

 bronchioles. At any rate bronchial asthmatic spasm is said to be relieved 

 by the subcutaneous injection of epinephrin (Jagic). 



Response of Smooth Muscle in the Skin. Usually smooth muscle that 

 is easily contracted through sympathetic stimulation is likewise readily 

 affected by epinephrin. The smooth muscle of hairs proves to be an ex- 

 ception. Here the response to sympathetic stimulation may be very marked 

 while epinephrin may have but slight effect in some animals while in 

 others the two effects run parallel. Elliott (b) suggests that the response 

 to epinephrin depends upon the extent to which the structures are com- 

 monly used, rather than upon the sympathetic irritability. 



The variable response to epinephrin injections in the arrectores pilorum 

 of different animals is one of the best illustrations of this dependence of 

 the reaction upon the varying functional use of the structure by each 

 animal. Elliott has observed that the hairs on the back of the domestic 

 cat are not easily affected by epinephrin (sympathetic stimulation easily 

 erects the hairs) while those on the scruff of the neck and down the middle 

 of the back on a fox-terrier are readily affected. The hairs on the tail 

 of the mongoose are erected with great ease by epinephrin. The domestic 

 cat does not exercise the function of the arrectores pilorum to any great 

 extent while in the terrier the practice is more common and the mongoose 

 is said to fluff its tail with every fleeting emotion. 



Birds illustrate the same generalization. Their feathers possess a sym- 

 pathetic innervation, but those birds which frequently erect their feathers 

 have the latter most easily moved by epinephrin. Thus the cock's feathers 

 readily respond while the hen's feathers are affected with some diffi- 

 culty. 



Response of Sweat Glands. Langley(a) was unable to induce sweat 

 secretion in the cat's paw either by intravenous or local subcutaneous in- 

 jections of epinephrin in spite of the fact that the sweat glands are sup- 

 plied by sympathetic fibers. Elliott tried to stimulate the sweat glands in 

 the human hand but a decrease in the secretion resulted, due probably 

 to the anemia produced. 



Dieden has been able to produce sweating of the cat's paw by the in- 

 jection of epinephrin into the pad of the foot but only after section of the 

 sciatic nerve or else during deep anesthesia. Intravenous injections or 

 subcutaneous injections in other regions were ineffective. 



Response of Pigment Cells. An agglomeration of the pigment gran- 

 ules in the retina of the frog due to epinephrin has been described by Klett. 

 This may occur even in the presence of light, which ordinarily causes 

 migration of the granules. 



