24 



PROFESSOR C. R. MARSHALL ON THE 



unable to turn over when laid upon its back. The effect is upon the nerve-endings 

 mainly as may be shown by electrical stimulation of the nerves and muscles after 

 the intoxication. 



According to Iodlbauer* the minimal paralytic dose for the edible frog is 0*005 mg. 



Fig. 4. — Clonic spasms of fore limb 

 of decerebrate cat produced by 

 2 mg. tetra-metliyl-amnionium 

 chloride intravenously forty- 

 five minutes after excision of 

 cerebrum and cessation of anaes- 

 thetic. Injection shown at X. 

 Time in seconds. 



H 



b 



t 



Fig. 5. — Reflex excitability during paralysis of respiration in decerebrate rabbit after 

 intravenous injection of 2 mg. tetra-methyl-ammonium chloride. Rabbit. 

 2200 g. Cerebrum excised 2.50. Both vagi cut. Atropine 5 mg. injected at 

 4.4. At points marked X animal was sharply blown upon. Letters as in 

 previous figures. 



p. g. body-weight; according to Santesson and Koraent 0"01 mg. p. g. body-weight. 

 The latter observers give as the minimal paralytic dose for the grass frog 0'12 mg. p. g. 

 body-weight. My own experiments with smaller frogs indicate that it is 0-08-0"09 mg. 

 p. g. body-weight. 



Dufaux| and Iodlbauer § describe fibrillary contractions as occurring in frogs 



* Loc. cit., p. 186. t Loc. cit., pp. 221, 222. J Loc. cit. § Loc cit., p. 188. 



