Rect. 

 Gl. 



+ + 



Ant. Rect. 

 and Valve. 



+ + 



Dist 



Int. 



+ + 



+ + 



- 



104 



contractions. The solvent for the drugs employed was 

 m/8NaCl: — 



Table 3. 



Experiment No. 20. 



Solution. 1^^*; 



NaCl + + 



Curari 1:1000 + + 



Codeine phosphate 1 : 1000 — — _ _ 



NaCl + - + 



Pilocarpine, which stimulates the motor nerve-endings in 

 various smooth-muscle organs, and particularly the intestine 

 of the vertebrate, immobilises the fly's intestine, but not nearly 

 so quickly as codeine. The contractions in preparations 

 immersed in 1:1000 solutions of pilocarpine in m/8 NaCl or 

 50 m/8 NaCl+ 1 m/8 CoCU slowly diminish in frequency and 

 amplitude, but may still persist after ten minutes. No trace 

 of stimulation could ever be observed. 



Chloretone, which is a general anaesthetic, causes 

 immediate cessation of movement when applied in 1 : lOOQ 

 solution. More dilute solutions, 1 :4000, cause a slow decrease 

 in amplitude and frequency, but decided contractions may 

 still persist after six or eight minutes of exposure to the 

 solution. 



In reviewing these results it is evident that the striated 

 muscle fibres of the fly's intestine differ in their reaction to 

 nerve excitants and depressants from both the striated and 

 the unstriated fibres which occur in the majority of mammalian 

 tissues. The most striking reaction is the instant immobolisa- 

 tion by codeine, in which respect of its behaviour the striated 

 muscle of the fly's intestine approaches more closely to the 

 smooth muscle of the mammalian intestine than to any other 

 mammalian muscle tissue. 



Effects of Drugs which affect Muscle Tissue or 

 Myoneural Junctions. 



Veratrine, which paralyses the relaxation of vertebrate 

 striated muscle, and henoe induces sustained contracture, 

 promptly, in 1:2000 solution, immobilises the fly's intestine. 

 It cannot be said, however, that the intestine is immobilised 

 in a condition of sustained contraction. No definite chans^es 

 of muscular tone were observed. Great increase of muscular 

 tone does occur when the fly's intestine is treated with adrena- 

 line. In such cases the increase in tone is evidenced by short- 

 ening and coiling up of the intestine. No such changes are 



