FiTCHETT. — Physiological Action of Tutin. 319 



In the first experiment (Exp. 135)^0-025 per cent, tutin — there was a 

 diminution in excitability : thus, the muscle in saline contracted with the 

 coil at 18 cm., three hours after the experiment began, while the corre- 

 sponding muscle in tutin contracted only at 15 cm. 



Where 0-05-per-cent. solution tutin was used (Exp. 137) the muscles 

 were equally excitable after two hours, but the muscle in the tutin had 

 been the more excitable of the two before immersion in the tutin. Thus, 

 before tutin was apphed it contracted at 30-5 cm., and two hours after 

 the application of tutin at 25-5 cm., while the control contracted at 25-5 cm. 

 and at 25 cm. 



Another experiment where the muscle was placed in 0-05-per-cent. solu- 

 tion tutin gave the following results (Exp. 138) : Before immersion in 

 tutin solution — A contracted at 36 cm. ; B (control) contracted at 32 cm. 

 Two hours after immersion in tutin solution — A contracted at 21 ; B con- 

 tracted at 23. 



In the experiment with 0-5-per-cent. solution tutin (Exp. 136) the 

 minimal stimulus before the apphcation of tutin for A was 28 cm., for B 

 34 cm. The muscle of B (control) and the nerve of A were then placed 

 in the tutin solution, and an hour and a quarter afterwards A contracted 

 at 33 cm. and B contracted at 27-5 cm. 



(For details of these experiments, see protocols.) 



The inference to be drawn from these few experiments is that tutin 

 has no striking action on nerve or muscle fibre ; but there seems to be a 

 diminution in the excitability in the muscle placed in tutin solution, due 

 either to an action on the nerve-terminations or to an action on the muscle 

 fibre. This would help to explain the weakness and loss of tone seen in the 

 later stages of tutin poisoning, especially well seen in frogs. 



It is possible that the action is one on the nerve-endings, for instances 

 are known of a poison {e.g., strychnine) acting as an irritant to nerve-cells, 

 and having at the same time a paralysing action on motor-nerve endings. 

 Nussbaum (27) states that picrotoxin in small doses stimulates, and with 

 slightly higher doses depresses, the activity of the peripheral nerve-termi- 

 nations. The same may be the case with tutin. 



1-1. Action on the Different Systems. 

 (a.) Alimentary System. 



Salivation is a marked feature in animals poisoned by tutin. It is an 

 early symptom, and usually precedes the vomiting, though it may be 

 present when vomiting is absent, as in Exps. 1 and 2. It is most profuse 

 where the dose is large, and in these cases is a source of danger in the later 

 stages by obstructing the respiratory passages. As a rule, it diminishes 

 when vomiting has occurred, and is not a marked feature in those animals 

 (rabbits and guinea-pigs) that do not ^'omit. Probably, therefore, it may be 

 an exaggeration of the saUvation which usually precedes the act of vomiting. 

 The saliva is thick and ropy, and hangs from the mouth in long tenacious 

 strings. 8ahva of this consistence suggests stimulation of the sympathetic. 



Vomiting is also an early symptom. It is not an invariable symptom, 

 being present in only two of the cats and in three or four of the pigeons 

 experimented upon. It is more hkely to occur if the dose be small. 



The salivation and the vomiting could both be explained as due to 

 stimulation of the vomiting-centre in the pons. That it is due to stimu- 

 lation of the centre is shown by the fact that it occurs when the poison is 



