PHARMACOLOGICAL ACTION OF TETRA-ALKYL- AMMONIUM COMPOUNDS. 29 



Experiment IV. — Eabbit, decerebrate. Weight, 1850 g. Fifth cranial nerves cut 

 distally to Gasserian ganglia. Anaesthetic stopped. 2.54. Respiration irregular 

 in rhythm. 



3.18. 0*5 mg. tetra-methyl-ammonium chloride injected. Transient stoppage of re- 

 spiration followed by deeper, regular, and more rapid respiration. The 

 blood-pressure fell from 80 mm. Hg to 68 mm. Hg, and with the onset 

 of respiration rose to 108 mm. Hg. It then gradually fell to 72 mm. Hg 

 (at 3.19£). 



3.20. 0*5 mg. again injected. Produced only slight depression of respiration. The 



blood-pressure was influenced as by previous injection, but to a somewhat 

 less extent. 



3.21. 1 mg. injected. Produced paralysis of respiration for twenty seconds although 



blood-pressure was less influenced than by previous injections. 



Experiment V. — Rabbit, decerebrate. Weight, 2000 g. Both fifth cranial 

 nerves cut. Anaesthetic stopped, 11.0. 



11.26. 2 mg. tetra-methyl-ammonium chloride injected. Respiration almost ceased 

 for two seconds immediately after injection, then increased in depth and 

 frequency for one minute, and subsequently returned gradually to normal. 



The blood-pressure (82 mm. Hg) rose slightly during the injection, 

 and then, with marked slowing of the heart's frequency, fell rapidly to 

 49 mm. Hg for a few seconds. A gradual rise to 71 mm. Hg followed, 

 succeeded by a gradual fall to 5 1 mm. Hg and a gradual return to normal 

 at 11.30. 



11.36. 1 mg. atropine injected. Slight transient stimulation of respiration and slight 



increase in frequency of heart. 



11.37. 2 mg. tetra-methyl-ammonium chloride injected. Respiration almost ceased 



for one second, then increased in frequency and gradually in depth for one 

 minute, after which it gradually returned to normal. 



The blood-pressure showed successively a transient rise to 85 mm. Hg, 

 a fall to 74 mm. Hg, a rise to 108 mm. Hg (at 11.38), a gradual fall to 

 67 mm. Hg (at 11.39). 

 11.40. l'5mg. tetra-methyl-ammonium chloride injected. Effects similar to previous 

 injection, but somewhat greater diminution of frequency of heart. 



Experiment VI. — Rabbit, decerebrate. Weight, 2250 g. Both fifth cranial 

 nerves cut. Anaesthetic stopped, 12.0. 



12.21. 1 mg. atropine injected slowly. 



12.25. 2 mg. tetra-methyl-ammonium chloride injected. Twelve seconds after com- 

 mencement of injection respiration increased markedly in depth and some- 



