TRANSACTIONS OF SECTION I. 805 



4. Is the distribution of fats uniform throug^hout the liver? It is found 

 to he so. 



6. In animals in the same condition is the percentage amount of fat in the 

 liver nearly the same P Ten observations show that the variation is usually 

 under 5 per cent., vsrhile the dift'erence in the amount of fatty acids is even 

 emaller. 



A. The Source of Liver Fats. 



I. Are they directly stored i'rom the fat in the food ? 



a. The amount of fats in the liver at diflerent pei-iods after food was estimated, 

 and, with the exception of a somewhat doubtful increase between twenty-four and 

 thirty hours after the meal, no change in the amount of fat could be determined. 

 Further experiments on this subject are beinp; carried on. 



b. Does the amount of fat bear any relationship to the amount of glycogen ? 

 As a result of a large number of estimations it is concluded that the fats bear 

 no relationship to the amount of glycogen. 



II. Are they formed from the fats of the adipose tissue ? 



a. Much of the work already pubHshed on phosphorus poisoning tends to 

 indicate that they are so formed. 



b. During starvation the amount of fats in the body falls to a much greater 

 extent than the liver fats, which undergo a comparatively small reduction. 



III. Are they formed during the katabolism of liver protoplasm? 



In the lyost-mortem liver kept for several hours at 40° (J. no change in the 

 amount of fats has so far been determined. Further experiments on this point 

 are required. 



B. The fate of the liver fats has not so far been sufficiently investigated 

 to justify any conclusions. 



4. On the Measurement of Simple Reaction Time for Sight, Hearing, and 

 Touch. By Professor W. Rutherford, M.D., F.E.S. 



Reaction time is the interval that elapses between the stimulation of a sense 

 organ and a motor response. The physiological process involved consists of 

 {a) an ati'erent factor — the stimulation of a sensory terminal and transmission 

 of an impulse along sensory nerve-fibres to the brain ; (b) a psychical factor 

 involving an act of sensory perception and the voluntary production of a motor 

 impulse ; (c) an efferent factor — the transmission of an impulse along motor nerve- 

 fibres, and muscular contraction. To render the reaction ' simple,' discrimination 

 is eliminated from the act of perception by repeating the same sensation again 

 and again without variation in its character ; and choice is eliminated from the 

 voluntary act by giving the same motor response again and again. In the 

 author's experiments motor response was given by the right forefinger closing 

 an electrical key. The stimulus for sight was the movement of a flag attached 

 to a lever ; that for hearing was a click given by transmitting an induction shock 

 through a telephone; that for touch was an induction shock or a mechanical 

 tap. The reaction time was ascertained by recording the moments of stimulation 

 and of response on a revolving cylinder and also on a pendulum myograph, and 

 measuring the interval by a tuning-fork. The pendulum myograph has not 

 hitherto been employed in such experiments. It is very advantageous in experi- 

 menting on hearing and touch. Successive curves are superimposed, so that 

 variations in the time of successive reactions are visible at a glance, and can be 

 readily measured. By photography the record can be readily printed or thrown 

 on a screen for lecture demonstrations. The reaction times, as measured by the 

 author's methods, differ considerably from those of some German observers. In 

 observations made on eight intelligent healthy men, varying in age from nineteen 

 to sixty -two, the reaction time for sight varied from 0-1662 second to 02202 second, 

 and was mostly between 0-20 second and 0*22 second. The reaction time for 

 hearing varied from 0-1448 second to 0T930 second, and was mostly between 

 0-15 second and 0-16 second. The reaction time for touch varied from 0-1416 



