342 Dr. A. D. Waller and Miss S. C. M. Sowton. [June 12, 



That of nerve 4, in neurine for 7 hours, was temporarily abolished and 

 permanently diminished. 



Exp. X. The sample of cerebro-spinal fluid used in this experiment 

 was one sent to us 3 weeks previously by Dr. Mott (and that had been 

 tested when fresh with a negative result). On the assumption that 

 the fluid had contained choline (which is comparatively inert), we 

 argued that it should be found to have increased in activity in conse- 

 quence of oxidation. This was found to be the case ; the negative 

 variation of the nerve was temporarily abolished by an immersion 

 lasting 1 hours. A similar effect is produced by the action of decom- 

 posed serum-albumin, vide infra Exps. XVII and XVIII. 



Exps. XI to XVI were made with various toxines sent to us by 

 Professor Wright and by Dr. Plimmer. Snake vemon (Exps. XI and 

 XII), caused temporary abolition, and we could not, by our method of 

 testing, find any difference of effect when the toxine was mixed with 

 its appropriate quantity of antitoxine solution (Exps. XIII and XIV). 

 Diphtheritic toxine (Exp. XV) and tetanus toxine also produced 

 temporary abolition. 



These few experiments, as far as they go, indicate that the toxines 

 in question are, as regards isolated nerve tested in this manner, sub- 

 stances of the second degree of toxicity. But we evidently need 

 further experiments. 



The last two experiments (XVII and XVIII) were made to see 

 whether the decomposition products of serum-albumin have a toxic 

 action. It is evident that they have, and that their toxicity is one of 

 the second degree, as defined above. 



EXPERIMENTS ON THE FROG'S HEART. 



In view of the well-known cardiac effects of muscarine, we undertook 

 an experimental survey of the influence of the group of related bodies 

 upon the action of the heart, taking as the most convenient case for 

 our purpose the isolated frog's heart and the suspension method, the 

 drug, in appropriate dilution being simply applied to the surface of the 

 heart. 



The general results of these observations were to the following 

 effect : 



1. Neurine, muscarine, choline, betaine (as hydrochlorides) bring 

 about diastolic arrest of the heart. 



2. The arrest thus produced is antagonised by atropine (as 

 sulphate). 



3. Neurine and muscarine are more active than betaine or choline. 

 The following records are illustrative examples selected from a series 



of upwards of 50 experiments, all giving concordant results : 



