August 30, 1906] 



NA TURE 



447 



THE ELECTRICAL SIGNS OF LIFE AND I : 

 THEIR ABOLITION BY CHLOROFORM.' 

 S it was not possible to show the actual experi- 

 ' merits, Dr. Waller illustrated his lecture by 

 diafjrams, and introduced his method of presentinj,'- 



A^ 



.N^r^i^. 



OrU Iftflt^ . 





: compared with electrical eflFect of light 



them on the screen by placing in the lantern smoked 

 plales on which he sketched in view of the audience 

 diagrams of the apparatus (battery, induction coil, 

 electrodes, galvanometer) em- 

 ployed in the experiments, 

 and showed the methods by 

 which the photographic re- 

 cords were obtained. 



The physiologist is engaged 

 in the task of learning how- 

 plants and animals absorb, 

 transform, distribute, and dis- 

 pense the energy stored in 

 food and manifested in each 

 act of life — in a word, of 

 studying the signs of life ; 

 and in the electrical change 

 which accompanies all chem- 

 ical change we have the most 

 delicate means of addressing 

 two questions to living 

 matter : Are you alive ? How- 

 much are you alive? 



Tissues survive the death 

 of the animal or plant. Six 

 objects were chosen as re- 

 presentative examples of 

 living matter — muscle, nerve, 

 retina of the eyeball, a green 

 leaf, a flow-er petal, and a 

 seed. The characteristic of 

 life is perpetual change, 

 metabolism — building up and 

 breaking down — anabolism, 

 and katabolism. From the records show-n of the elec- 

 trical responses to excitation of muscle and nerve, it 



1 Abstract of lecture delivered by Dr.Augustus D. Waller, F.R.S., to the 

 members of the British Association at York. 



NO, 1922, VOL. 74] 



v\as deduced that isolated nerve, by reason of its show- 

 ng no fatigue, but giving perfectly regular responses, 

 is a favourable symbol of living matter on which to 

 study the effect of drugs and reagents. I'^rom these 

 experiments was proved the fact that chloroform is 

 eight times more powerful than ether, and that 2 per 

 cent, vapour of chloroform is 

 I the safe dose. Dr. Waller 

 attributed deaths from over- 

 dose of chloroform to inatten- 

 tion to the great scientific 

 principle of measurement. 



Records were shown of the 

 electrical effects produced by 

 a series of illuminations of the 

 ej'eball, and of similar effects 

 produced by pressure on the 

 eyeball and by electrical 

 excitation ; Dr. Waller at first 

 thought these latter effects 

 1 were the same as those pro- 

 duced by light on the retina, 

 and called them " blaze cur- 

 rents," but afterwards found 

 they w-ere characteristic of all 

 living tissues. The petal of a 

 flower and living seeds give 

 blaze currents. 



Dr. Waller described his 

 records of the electrical effects 

 of light on a green leaf ; sun- 

 light and the arc light were 

 used ; it seemed natural that 



J the vegetable retina should be 



sensitive to light ; the re- 

 sponse is a double one, first 

 negative then positive, dissimilation then assimilation ; 

 the carbonic acid function of the green leaf is prob- 

 ably attended bv electrical effects ; positive or assimil- 



of the electrical efifecis of light on leaf of N; 



caused by 4 per cent. COo. 



ative effect is far more pronounced in vegetable than 

 in animal protoplasm (see Fig. i). A leaf of Nico- 

 tiana was illuminated for five minutes at intervals of 

 ten minutes, and gave a deviation of the magnet of 



