Related to Forbes to Sherrington - 16 January 1916 (I-2-93 (iv))
Description:

'I have during the last four weeks obtained some results which I believe will interest you and Miss Buchanan.

I found that by placing the back of my hand and wrist in ice water [inserted: '(7° C)'] without letting it touch the palm I could lower the temperature of the palm appreciably; a thermometer secured to the palm with surgeon's [plaster?] showed a fall of about 3°C in 15 minutes. From this I concluded that complete immersion of the hand and half the forearm in ice water (6° or 7°C) for a similar time would lower the temperature of the entire hand still more than that. By using Piper's technique, slightly modified, I recorded the action current of the first dorsal interosseous muscle [crossed through: 'first with the'] in voluntary contraction, first with the hand at normal temperature, second after 15 minutes immersion in water at about 7°C, and finally after 10 or 15 min immersion in water at 45° to 47°C.

This simple chilling produces in every case a striking slowing of rhythm with greatly increased amplitude of individual excursions. I enclose prints from my films taken from a student who is working on it with me. I have obtained this result regularly in three or four experiments in which I have used this procedure. I intend to repeat it two or three times more to make sure, and then publish the results with a discussion of the recent work of Lucas and Adrian. It seems to me that with a proper consideration of the "relative refractory period" there is a ready answer to Piper's objection to some of Miss Buchanan's contentions, viz. that the observed muscle rhythm is not an index of the rhythm of nervous discharge.

I think I can show that although, as Piper states, a muscel stimulated by 200-300 induction shocks a second will respond with action currents at the same rate, still it is possible that nerve impulses at a rate of 500 - 600 per second may only evoke 50 propagated disturbances per second in the muscle.'

 

Related to Forbes to Sherrington - 23 July 1913 (I-2-93 (i))

Related to Forbes to Sherrington - 26 May 1916 (I-2-93 (v))
Description:

'I wonder if you received a letter I sent during the winter enclosing prints from my records showing the effect of chilling the whole forearm in ice water upon the electromyogram taken from a muscle in the hand. We found this local change of temperature produced a marked slowing of rhythm, thus supporting Miss Buchanan's findings in the frog, and proving, I think, that Piper's 50 per sec rhythm is not that of central discharge along the motor nerve. Furthermore, why should a nerve fibre have a refractory period of about 10[?] if it is only called on in the performance of its normal function to transmit an impulse once every 200 or so? As soon as I can find time to write it I mean to publish this observation together with a discussion answering Piper's objection to Miss Buchanan's view, by making use of some of Adrian's and Lucas's principles.'