178 THE DUCTLESS GLANDS 



movements for a short time. More commonly, however, there 

 is produced a shallowing of the respirations, which persists for 

 a certain period and then gradually passes off. In the dog no 

 stoppage of respiration was ever obtained, but the respirations, 

 although proceeding with an ordinary rhythm, were for a 

 time slightly shallower. Other observers have also noted this 

 effect of adrenal extracts upon the respiration. It is nearly 

 always most marked with the first injection ; with repeated 

 injections the effect as a rule soon becomes trivial, and always 

 becomes so if the injections are repeated a sufficient number 

 of times. The subject has been recently investigated by 

 Langlois and Garrelon. These authors seem to have obtained 

 very considerable effects in the case of the dog ; they report 

 that if adrenalin be injected into a dog, expiratory apncea 

 sets in simultaneously with the beginning of the rise of 

 blood-pressure. The duration of this apncea is not constant. 

 In most cases the respiratory movements begin again while 

 the blood-pressure is still very high, and the respiration has 

 most frequently returned to its regular type before the blood- 

 pressure has returned to normal. If the injections are repeated 

 in rapid succession, the influence disappears. After section 

 of the vagi, the adrenalin injection has a much less marked 

 action on the respiration. There is then a slowing of the 

 movements, but no apnoaa. Air rich in oxygen favours the 

 occurrence of this apnoea, while an atmosphere with a large 

 proportion of carbon dioxide hinders it. 



Oliver and Schafer discovered that adrenal extracts prolong 

 the curve of contraction of the skeletal muscles, both in the frog 

 and in the dog, though the period of latency is not increased. 

 They were convinced that the curve is not a fatigue curve, but 

 that it is comparable rather to the effect of a slight dose of 

 veratrine. This effect has since been noted by many observers. 

 Boruttau says that the phenomenon occurs in excised curarized 

 muscle, and reminds one of the first stage of fatigue. Panella 

 describes an anticuraric action of adrenin (" hemostasine ") 

 and states that it (" myosthenin," on this occasion) increases 

 the activity of fatigued striated muscles. Cannon finds that 

 the improvement of muscular contraction which apparently 

 results from adrenal secretion (when the blood-pressure is 

 controlled) is too slight to account for the increased muscular 

 power observed during excitement. The main source of power 



