220 KANSAS UNIVERSITY SCIENCE BULLETIN. 



of salts on the activity of adrenalin; this one deals with the 

 inhibition of the pupil reaction. 



EXPERIMENTS UPON THE FROG. 

 Method. 



In preparing the frog for the experiment the animal was 

 first anesthetized with ether, then fastened onto the holder 

 with ordinary binding tape, after which an occasional drop 

 of ether was sufficient to prevent struggling. The lower part 

 of the abdominal aorta and the two iliac arteries were exposed 

 by removing the oscoccygis (see Schulz, loc. cit.) , after which 

 the canula (three-way for the purpose of cleaning) was in- 

 serted into the right iliac when this vessel was large enough, 

 otherwise the abdominal aorta itself was employed. The 

 canula was connected to a Hiirthle manometer, using as a 

 transmission fluid the solution suggested by Schulz — 10 per 

 cent dextrose and 1 per cent ammonium oxalate. The injec- 

 tions were made into the crural vein of the left leg through a 

 glass canula, which was tied into this vessel and supported 

 by a clamp. It is necessary to support both canulse in a favor- 

 able position, because of the great tenderness of the frog's 

 blood vessels. Throughout the experiment the animal was 

 kept covered with a moist cloth to prevent drying of the skin 

 and other undesirable sensory stimuli, which, according to 

 Schulz, cause a marked change in the blood-pressure. 



The respiratory curve was obtained by the use of two tam- 

 bours — one placed under the animal's head and in contact with 

 the skin over the submental muscles; the other placed on a 

 stand and operating a writing lever. The results obtained 

 were, however, very unsatisfactory, because of the irregular 

 respiration of the frog when the animal is disturbed. 



Frogs of about 100 gm. weight were chosen, so that a con- 

 stant dose of the solutions (0.25 c.c.) could be used. 



I had no occasion to test the reflex stimulation of the vagus 

 through the sensory nerves other than the optic, on the eff'ect 

 of which Schulz {loc. cit.) makes the following remark: "Es 

 war zur Hervorrufung von Vaguskurven gar nicht einmal 

 notig, durch auflfallende Bewegung in der Nahe der Augen 

 einen Reiz auszuuben, sondern es genugte das erscheinen eines 

 fremden Gegenstandes innerhalb des Gesichtsfeldes schon auf 

 weite Entfernung hin." In view of this statement, and be- 

 cause it is difficult to avoid slight changes in light and other 



