mVERTEBRATA, CRYPTOGAMIA, MICROSCOPY, ETC. 



411 



It was now necessary to investigate the action of different kinds of 

 coloured light on the excretion of carbonic acid ; the following are 

 the mean results : — 



Uninjured frog 

 „ bird 

 „ rat 



Blind mammal 



Darkness. 



100 

 100 

 100 

 100 



100-5 

 128 

 111 

 109 



Blue-violet. 



115 

 139 

 140 

 114 



112 

 142 

 137 

 113 



Light has, then, a considerable influence on metabolic activity ; it 

 increases the excretion of carbonic acid and the ingestion of oxygen ; 

 but this influence is not only mediate through the eyes, it obtains 

 through the skin, for it is seen in eyeless animals. When the eyes 

 only or the skin only are affected the result is less than when the 

 whole animal is brought under its influence. The tissues are no less 

 affected than the whole body. The chemical rays have greater eftect 

 than the heating ones, and the result that light has a chemical influ- 

 ence on metabolism cannot be evaded. 



Alcohol in Animal Tissues during Life and after Death.*— In 

 order to verify the truth of the statement that flesh superficially 

 coagulated would rai)idly putrefy under conditions in which well- 

 cooked flesh would remain sound for many weeks, M. J. Bechamp 

 coagulated some horse flesh by immersion for ten minutes in boiling 

 water, then wrapped it in a closely woven cloth, and placed aside for 

 eight days. At the expiration of that time, the meat was found in an 

 advanced state of decomposition, and the muscular striation had 

 disappeared, although the air had not penetrated to the interior of 

 the substance, whilst Bacteria and Vibrios abounded. By methods 

 described in the original memoir, the author isolated and identified 

 about 0*8 gram of alcohol and 10 grams of sodium salts formed by 

 acetic, butyric, and otlier acids. The alcohol was converted into 

 aldehyde, and oxidized to acetic acid, so that its identity was 

 established beyond doubt ; within certain limits the quantity obtained 

 was larger, tlie further the extent of the decomposition. 



It would seem, therefore, that tlie phenomena accompanying 

 putrefaction are very closely allied to those belonging to fermenta- 

 tion properly so called, perhaps more directly with those of the 

 butyric fermentation. By tlio same process alcohol was obtained 

 from tlie fresh tissues. The brain of sheep gave a larger quantity 

 than the liver, but the largest quantity was obtained from tlic brain 

 of an ox, which furnished suflicient alcohol to measure with the 

 hydrometer. It may be argued, therefore, that in medico-legal cases, 

 the detection or sejiaration of alcoliol from j)utrid or healtliy tissues, 

 is not sufficient evidence to show that alcohol has been administered 

 at all, still less that this liquid has boon the cause of death. 



*'Comptc8 RenduH,' l.vxxix. (1879) p. ,')73 ; see 'Joiirn. Chom. Sor." AKsfr,, 

 xxxviii. (ISHO) p. 171. 



2 E 2 



