107 



to the rectum and rectal glands as well as to the intestine. 

 Previously immobile preparations, by several brief exposures 

 to adrenaline followed by a return to NaCl solution, could be 

 converted into preparations which were notably active in every 

 part, displaying simultaneously intestinal peristalsis, rectal 

 contractions, and powerful and rapid contractions of the rectal 

 glands. 



The second group of substances — ergotinine, ergamine, 

 ergotoxine (Burroughs, Wellcome), and digitaline (Merck) — 

 all alike produced complete inhibition of intestinal and rectal 

 movements in concentrations of 1 : 1000. In more dilute solu- 

 tions (1:10000) intestinal peristalsis was inhibited immedi- 

 ately, and at a much later period the rectal contractions were 

 also inhibited. In a number of instances, however, very dilute 

 ergotoxine or ergamine (1 : 100000) definitely stimulated the 

 contractions of the rectum and rectal glands, either increasing 

 their amplitude or initiating them when they were otherwise 

 absent ; in other words, the action of these, drugs was in every 

 way the opposite of that of adrenaline. Their action resembled 



Ca 

 the eflFect of reducing the ^^ ratio, or, in other words, of 



Ca 

 raising the-p^ thresholds of the tissue. 



Pituitrine, in dosages of one or one-tenth mil. Parke 

 Davis "O" pituitrine per 20 cc. of solvent produced a dual 

 efiPect, as, indeed, it usually does in mammalian tissues. The 

 first effect was definite stimulation, especially of the rectum 

 and rectal glands, this being followed, usually within a minute, 

 by complete immobilis::.tion of the preparation. This diphasic 

 action of pituitrine, which is characteristic of its action upon 

 mammalian blood pressure (fall followed by a rise), is attri- 

 buted by the majority of authors to an admixture of two or 

 more principles of diverse action. It should be noted that 

 the secondary inhibition could not have been due to the 

 admixture of chloretone contained in this solution, since a like 

 concentration of chloretone, without pituitrine, failed to exert 

 a like effect. 



Discussion. 



In general, it may be stated 'from the foregoing results 

 that the fly's intestine is comparatively indifferent to those 

 agencies which, in the vertebrate, act primarily upon nervous 

 tissues or upon striated skeletal muscles. On the other hand, 

 those agencies which, in the vertebrate, act powerfullv upon 

 the myoneural junctions of smooth muscle, or upon smooth- 

 muscle fibres themselves, also exert characteristic actions upon 

 the muscle of the fly's intestine. The muscle fibres of the fly's 



