PHYSIOLOGY. 



695 



be found in ordinary records. From these 

 and other results he concludes that there is a 

 period of some '005 of a second (net latency) 

 during which certain molecular changes, neces- 

 sary for its energy to become visible, take place 

 in muscle. The influence of the elasticity of 

 muscle or the rate of propagation of the wave 

 of contraction can only come into operation 

 after this period. 



The study of the action of caffeine upon vol- 

 untary muscle is one of especial interest, be- 

 cause different observers have often obtained 

 very different results. In taking the subject 

 up again for investigation, Drs. T. Lauder 

 Brunton and J. Theodore Cash have kept in 

 vie\v the facts that the action which a sub- 

 stance is alleged to have upon a living organ- 

 ism may vary according to the nature of the 

 drug; according to the nature of the organ- 

 ism; and according to the conditions (of tem- 

 perature, duration of observation, dose, etc.) 

 under which the experiments are made. So 

 far as described in their paper, the experi- 

 ments of the authors have been directed to the 

 amount of caffeine producing rigor, and to the 

 effect of certain acids and alkalies on caffeine 

 rigor. 



Whatever view may be entertained as to the 

 nature of the electric currents present in an 

 injured muscle or nerve, whether they be re- 

 garded as pre-existing in the uninjured condi- 

 tion or as being developed through injury, 

 such currents exist in the injured condition. 

 They have been made the subject of investiga- 

 tions, with improved apparatus, by Drs. Henry 

 C. Chapman and Albert P. Brubaker, who 

 have sought to demonstrate their presence in 

 muscle and nerve, and to determine their elec- 

 tro-motive force. The method of these au- 

 thors has been applied to the gastrocnemius 

 muscle and the sciatic nerve of the frog, and 

 they have determined that the electro-motive 

 force of the muscle is more than three times as 

 great as that of the nerve. 



John Campbell, of Johns Hopkins Univer- 

 sity, has found that when curarized muscles 

 are moderately weighted and stimulated with 

 electricity, the stimulus starts from only one 

 electrode viz., the cathode on closing and the 

 anode on opening the current ; while with in- 

 significant weights the muscle is stimulated at 

 both anode and cathode, with equal and simul- 

 taneous stimuli. 



Poisons. An investigation has been under- 

 taken by Dr. Weyl of the toxic or non-toxic 

 properties of the coloring matters derived from 

 coal-tar, including especially those that might 

 be employed for the coloration of food-materi- 

 als. The author first tested the nitroso and 

 nitro derivatives of benzol and phenol, and, 

 taking phenyl green as a typical representa- 

 tive, found the first to be non-poisonous. The 

 nitro-derivatives which he examined namely, 

 picric acid, dinitro-kresol, and Martin's yellow 

 he found to be poisonous ; the sulpho-com- 

 pounds of the last-named matter were barm- 



less ; two of these naphthol yellow and brill- 

 iant yellow are articles of commerce. The 

 difference points to a relationship between the 

 chemical constitution and physiological action 

 of these bodies. 



The general physiological action of carbcnic 

 monoxide was well illustrated in a case of fa- 

 tal poisoning by that gas at Troy, N. Y., of 

 which Prof. W. P. Mason gave an account be- 

 fore the American Association. Owing to a 

 break in the mains, a quantity of fuel-gas 

 passed beneath the frozen crest of the earth 

 and escaped into the adjoining houses. Three 

 deaths and a number of serious illnesses result- 

 ed. The fuel-gas contained about 40 per cent, 

 of carbon monoxide and was practically odor- 

 Very searching autopsies were made with 

 the result of finding nothing abnormal except 

 the bright, cherry-red color of the tissues and 

 the vivid redness of the blood. The physician 

 making the autopsies was seized with giddiness 

 and great oppression in the chest, calling strong- 

 ly to mind the symptoms described by Sir Hum- 

 phry Davy when he so rashly experimented 

 upon himself with carbon monoxide. The 

 presence of carbon monoxide in the blood was 

 shown by the spectroscope, the characteristic 

 absorption bands being strongly marked. Al- 

 though now twenty months since the time of 

 its removal from the body, the blood still pre- 

 serves its brilliant redness and gives the carbon 

 monoxide bands as distinctly as ever. 



The toxic milk ptomaine, tyrotoxicon, ac- 

 cording to Braithwaite's " Retrospect." is, 

 chemically speaking, diazo-benzole. It is de- 

 veloped in milk by the growth of a micro-or- 

 ganism which multiplies rapidly under favora- 

 ble conditions. These are principally the ex- 

 clusion of air, entirely or to a great extent, and 

 a temperature approaching 36. It is observed 

 under these conditions if milk, as it is drawn 

 from the cow, is placed in cans and they are 

 tightly closed. 



It is shown in a memoir by MM. Ronx, and 

 Chamberland, to which M. P'asteur has called 

 attention in the French Academy of Sciences, 

 that the septic vibrion, a living ferment analo- 

 gous to the butyric vibrion, develops soluble 

 chemical products, which gradually act as an 

 antiseptic on the organism itself. These prod- 

 ucts, introduced in sufficient quantities into the 

 body of the guinea-pig, confer absolute immu- 

 nity from the attacks of the virus, to which 

 that animal is specially susceptible. 



Experiments by Dr. R. H. Chittenden have 

 shown thr.t uranium is an irritant poison tend- 

 ing to destroy the life of the intestinal and re- 

 nal tissues. Enteritis, or acute catarrhal in- 

 flammation, was easily induced by the adminis- 

 tration of small doses of its salts. In toxic 

 doses it causes absolute annria; in smaller doses, 

 merely acute pareuchymatous nephritis; in mi- 

 nute doses it has a diuretic effect. Oxalate of 

 lime crystals in the urine, and glycosuria were 

 constantly noted in cases of poisoning by ura- 

 nium. 



