1911.] 



Action of Soluble Substances in Frogs. 



99 



derived from experiments made with three alkaloids presenting different 

 types : adrenaline, strychnine, and morphine. 



Adrenaline. — The dilating effect upon the pupil was the leading reaction. 

 An injection of 1 c.c. of adrenaline causes in cardiectomised frogs sooner or 

 later a dilatation of the pupil. It may appear in less than an hour (dorsal 

 and lateral lymph sacs), or after two hours (abdominal cavity or in one leg). 

 When injected into both legs the dilatation appears much sooner. Cutting 

 both sciatic plexuses does not interfere with the appearance of the dilatation. 

 The dilatation sets in even if the animal is suspended by the head. When 

 injected into a lateral lymph sac the pupil of the corresponding side dilates 

 first, to be followed 20 or 30 minutes later by a dilatation of the pupil of the 

 other side. 



When the frogs are kept moist and at a low temperature the pupils dilate 

 after an injection of adrenaline even three or four days after cardiectomy, 

 provided the eyes are not dried out. In the latter case the presence of 

 adrenaline in the orbit is easily demonstrated by placing a fresh bulbus from 

 a normal frog with the corneal surface inside. In this manner the pupils of 

 several normal bulbi may become dilated by being placed in the orbit 

 consecutively one after another. 



These experiments demonstrate that adrenaline may become distributed 

 through the entire body of a frog in the absence of the circulatory apparatus. 

 In the case of the migration from a lateral lymph sac to the eye of the 

 opposite side, the adrenaline has to pass through fairly solid membranes and 

 voluminous masses. Diffusion alone will probably not accomplish it ; osmosis 

 will have to assist in the process. Gravity is not an essential factor. 

 Movements of the animal, or " vital " activities of cells, are not parts of this 

 peripheral mechanism of distribution. 



Strychnine. — Frogs survive cardiectomy an hour or two, or even longer, 

 .according to the temperature at which they are kept ; spontaneous and reflex 

 movements disappear gradually. Strychnine exerts a definite influence upon 

 the course of life after cardiectomy. When about 10 mgrm. of strychnine 

 are injected, after a temporary insignificant depression, the animal develops 

 in 30 or 40 minutes a definite tetanus. These animals invariably survive the 

 controls, kept under the same condition, by an hour and longer. When a 

 somewhat larger dose is administered, the first effect is a definite depression 

 which may be accompanied by a semi-paretic state. Suddenly the animal 

 asserts itself, becomes hypersesthetic, and develops a tetanus. When a still 

 larger dose of strychnine is injected, the essential effect is an early onset and 

 development of an unmistakable paralysis ; the latter can no longer be 

 overcome by the hyper-excitability which ineffectively manifests itself later. 



