Aug. 4, 1882.] 



♦ KNO\VLEDGE 



161 



cnrrent will pass through the conductor, and so equilibriate 

 the two potentials. It is as impossible to say what this 

 potential is due to, as it is to assign a cause for chemical 

 affinity. All we can do is to say it exists, and that to a 

 considerable extent it is governable. 



It is commonly accepted that if we plunge a red-hot 

 iron ball into water, both the water and the iron endeavour 

 to impart heat one to the other in proportion to their 

 respective temperatures, until ultimately equilibrium is 

 attained, when no further transmission of heat takes place. 

 Now we should be able to see that when the water and the 

 iron have arrived at the same temperature, no further 

 change will take place, or, in other words, equilibrium is 

 established, which will endure until a third body at a 

 different temperature is introduced, or until the tempera- 

 ture of one of them can be raised or lowered. There 

 must, then, be a difference of temperature to produce what 

 we may venture to call a " flow of heat." A close analogy 

 may be observed in electricity. A conductor connecting 

 two bodies at different potentials is traversed by a current 

 the intensity of which is equal to the difference between 

 the potentials, and this difference is called the electro- mot tve 

 force. 



HOME CURES FOR POISONS. 



MERCURY, in the metallic shape, often, perhaps 

 generally, passes through the body without pro- 

 ducing any harm, but it is not so safe to take it as many, 

 judging from such cases of immunity, imagine, for it may 

 become oxidised, and cause serious mischief in that form. 

 Howeser, the risk from mercury in this form, or applied 

 as a metal to the skin, need not occupy much of our atten- 

 tion, since there are few persons so foolish as to try experi- 

 ments from which no good can conceivably result, and 

 serious harm may. 



The chief forms in which mercury may be taken so as to 

 produce poisonous effects are the two chlorides — corro- 

 sive sublimate (formerly known as the bichloride, per 

 chloride, or oxymuriate of mercury), and calomel, the sub- 

 chloride or dichloride of mercury. Cinnabar, or vermilion, 

 the red sulphide of mercury, is also poisonous, but it is 

 not likely to occasion any domestic anxieties. 



When the use of mercury in any medicinal form, but 

 especially the corrosive sublimate, has been continued 

 too long, or in too large doses, the system suffers in several 

 characteristic ways. The brain and spinal chord are in a 

 special manner affected, and serious diseases of the lirain 

 have been known to follow. The liml)streml)le and quiver, 

 and the tissues show a morbid sensibility which is very 

 readily recognised. The secretion from the skin is abun- 

 dant, and the salivary glands, becoming irritated, pour out 

 large quantities of saliva. When poisonous doses have 

 been taken, the effects on the salivary glands are not so 

 conspicuous, and indeed are often not noticed at all. In 

 severe cases, the .symptoms then rastmble very closely 

 those observed in cases of arsenical poisoning, only they 

 come on more quickly. An intense constriction of the 

 throat is a marked feature of severe cases ; violent vomiting 

 and pains in the pit of the stomach are nearly always 

 noticed. 



Antidotes for mercury are selected with the object of 

 preventing or limiting, as far as possible, its local action. 

 Corrosive sublimate has the power of combining with albu- 

 minous substances, and therefore, when swallowed, abstracts 

 albumen from the coats of the stomach. In the process 

 calomel is formed. The poisonous action results from this 

 lombination witli the albumen of the stomach. Therefore, 



to prevent or limit the poisonous action, albumen must te 

 supplied from without. If white of egg, which is pure 

 albumen, be taken into the stomach in good time, the coats 

 of the stomach will be preserved from injury. According 

 to Orfila, the proper proportion is the white of six eggs to 

 half a-pint of water. Decoction of bark or gall-nuts may 

 also be used with advantage. If the pains have beeome 

 intense before such remedies have been tried, we must 

 assume that the poison has already acted injuriously upon 

 the coats of the stomach. In this case, only a medical 

 man can be trusted to suggest suitable remedial measures, 

 the action of which will usually be more or less tedious. 

 Warm baths, diluent drinks, and a diet of milk and farina- 

 ceous food, are suitable when the stomach has been thus 

 injured. But usually medical advice can be readily obtained 

 in time for the initiation of remedial measures of this kind. 



THOUGHT-READING. 



By the Editor. 



IN endeavouring to explain those phenomena which 

 come out, after careful elimination of doubtful cases, 

 we must be careful to avoid equally undue confidence and 

 scepticism. For my own part, I am disposed to agree wr^ 

 Professor Barrett in considering that the assumption of ft 

 priori impossibility is more to be deprecated in th« pre- 

 sent state of our knowledge of Nature. There is very 

 little fear that science will accept any wild hypothesis in 

 explanation even of phenomena most unlike those which 

 have hitherto been brought within its sphere; for the 

 corrective capacity of science, already strongly developed, 

 increases daily. On the other hand, there is alwaj-B 

 some degree of danger that questions of interest 

 may unwisely be put on one side as not worth inqiiiring 

 into, because they do not at first seem explicable by 

 known physical laws. The two dangers are, howevrr, 

 closely related together. It is noteworthy that the mind 

 which most recklessly rejects evidence which seems newur 

 strange, is the readiest eventually to accept the most 

 wildly impossible theories. It appears to me that Professor 

 Barrett and his colleagues very fairly present the it jrl^H 

 difficulties in this case. Apart from the legitimate grounds 

 of suspicion, open — as they say — to all who have chanced 

 to encounter the alleged phenomena in their vulgarest or 

 most dubious aspects, " it is inevitable that, as the area of 

 the known increases by perpetual additions to its recog- 

 nised departments, and by perpetual multiplication of 

 their connections, a disinclination should arise to bi-eak 

 loose from association, and to admit a quite new depart- 

 ment on its own independent evidence. And it cannot 

 be denied that the department of research towards which 

 the foregoing experiments form a slight contribution, pre- 

 sents as little apparent connection with any ascertained 

 facts of mental and of material science. PsychologicAl 

 treatises may be searched in vain for any amount of trans- 

 mission of mental images otherwise than by purely sensory 

 channels." 



Yet the only explanation science can seek is a physical 

 one. It is open, Prof Barrett considers, to surmise that 

 tliere is some sort of analogy to the familiar phenon.curn 

 of the transmission and reception of vibratory energy. 



We are led along this line to conceive that some asso- 

 ciation may exist between the phenomena of so-called 

 tho\ight reading, and those strange stories of apparitions at 

 the time of death or of intense suffering, which Iiave been 

 narrated by so many persons of good repute (by so many, 



