4() 



KNOWLEDGE 



[Nov. 18, 1881. 



in the field (not giving up liunting, but restraining his zeal 

 on those occasions when the clay's run promised to be liardcr 

 than usual). 



The ellect of wLno used regularly, not in pint draughts, 

 is in many cases undoulitedly good where the memory is 

 apt to fail. We have an illustration of this in the 

 following case, Ix-longinf; to tlie first of the two classes 

 above considered. A gentleman whose mental and physical 

 powers had been severely taxed, lost all power of recol- 

 lecting rt'ceut events. " Whilst engaged in active conver- 

 sation, he was able, by a strong effort of the will, to retain 

 possession of the ideas suggested by others to his mind ; 

 but if there were the slightest interruption, even to the 

 extent of a minute, in the conversation, he lost all recol- 

 lection of wljat he had been previously saying. This 

 gentleman had been living for some weeks below par, with 

 the view of enabling him to perform an amount of urgent 

 mental work, requiring for its execution the lengthened 

 concentration of a clear and vigorous intellect. He had 

 been in the habit of drinking a fair portion of wine, but 

 had unwisely abandoned the use of stimulants, fancying 

 that by so doing he would be better fitted for clear-headed 

 mental occupation." Under Dr. Forbes Winslow's advice, 

 the patient " lived generously, took iron tonics, quinine, 

 and valerianate of zinc, and resumed his daily quantity of 

 wine. This treatment eventually restored his memory to 

 a state of health." Dr. Forbes Wiuslow adds that he has 

 known other instances of temporary loss of memory cured 

 within a short time by the free use of tonics and 

 stimulants. " In these cases," he says, " the brain is 

 generally in a starved and impoverished condition, arising 

 from a deficient supply of blood ; it is in a state of 

 enervation and inanition." On the other hand, the 

 excessive use of stimulants produces unmistakably mis- 

 chievous effects. Temporary attacks of loss of memory 

 have been caused by intemperance. " By an old Spanish 

 law," Dr. Winslow mentions, " no person was admitted 

 into the witness-box to give evidence in a disputed case 

 who was proved to indulge in habits of intemperance, as 

 an excessive use of stimulants was considered to weaken 

 and destroy the memory." 



(To he continued.) 



INTELLIGENCE IN ANIMALS. 



THE next case cited also relates to the apparent exercise 

 of reasoning faculties by rats, and is interesting, 

 because probably their action was guided by the sense of 

 hearing, rather than by that of smell. " Some years ago," 

 says the narrator, " a plumber told me that he had, on 

 several occasions, been called in to examine into the cause 

 of leakage of water-pipes under the flooring of houses, and 

 had found that the rats liad gnawed a hole in the leaden 

 pipe to obtain water, and that gieat numbers of them had 

 made it a eoniinon drinking-placo, as evidenced by the 

 quantity of dung lying about. The plumber brought me a 

 piece of leaden pipe, about three quarters of an inch in 

 diameter, and one-eighth of an inch in thickness, penetrated 

 in two places, taken by himself from a liouse on Haver- 

 stock-hill. There are tlie marks of the incisors on the 

 lead as clear as an engraving ; and a few hairs and two or 

 three of the rat's whiskers have been pinched into the metal 

 in the act of gnawing it This crucial proof of brute 

 intelligence— for a rat will not drink foul water — interested 

 me so much that I ventured to send an account of it to 

 Dr. Charles Darwin, asking his opinion on the means by 



which the rats ascertained the presence of water in tho pipe. 

 To this he replied : ' I cannot doubt about animals rea.soiiing 

 in a practical fashion. The ca.se of the rats is very fturious. 

 Do they not hear the water trickling 1 ' " TDiis explauia- 

 tion would go far, it would seem, to do away with the idea 

 that tho rats in this case had rea.soned, seeing that if they 

 recognised the presence of water by the sense of liearing, 

 their action in biting their way through to wliat tliey 

 wanted would correspond precisely with what we have 

 been taught (erroneously, in all probability, but that w a 

 detail) to regard as instinctive. The narrator, however, 

 did not read Dr. Darwin's reply in this sense. " It may Ije 

 conceded,'' he says, " that this explanation is the most pro- 

 bable, and if it be the true one, we have an example of on 

 animal using his senses to obtain the data for a process of 

 reasoning leading to conclusions about wliich he is so 

 certain that he will go to the trouble of cutting through a 

 considerable tliickne.ss of lead. Obviously man could do no 

 more under the same conditions." If the rats had shown 

 in their boring operations some special aptitude for securing 

 most conveniently, with the least possible overflow, the 

 water they required, this would be a just inference. But 

 as we know no more than that, having found, probably by 

 the sense of hearing, that water was present in the pipe, 

 they bored their way through to reach it, we have in reality 

 no more proof of reasoning power than is afforded by the 

 familiar action of mice in biting their way through the 

 wooden or card casings of boxes of edibles thev like, of 

 whose presence within such boxes the sense of smell has 

 convinced them. 



This objection is well put by Mr. Henslow in a letter 

 discussing this particular case, and Dr. Darwin's comments 

 thereon, only, as it seems to us, he carries the objection 

 rather farther than it will fairly go, extending it to cases 

 to which we think it can hardly be applied. " It has 

 always seemed to me," he says, " that brute reasoning is 

 always practical, but never abstract " (but he tries to 

 show that there is very little reasoning at all in the 

 matter). '"They do wonderful things, suggested by the 

 objective fact before them ; but, I think, never go beyond it. 

 Thus, a dog left in a room alone, rang the bell to fetch the 

 servant. Had not the dog been taught to ring the Itell 

 (which, on inquiry, proved to have been the case), it would 

 have been abstract reasoning ; but it was only practical. The 

 Arctic fox — too wary to be shot, like the first, who took a 

 bait tied to a string, which was attached to the trigger of a 

 gun — would dive under the snow and so pull the bait 

 down below tho line of fire. This is purely practical 

 reasoning ; but had the fox pulled the string first out of 

 the line of fire, in order to discharge the gun, and then to 

 get the bait, that would have been abstract reasoning, 

 ^\hich he could not attain to." This, however, is assuming 

 more than can be proved ; the fox in the case referred to 

 did not act in the way which would have implied abstract 

 reasoning ; we do not know that no fox has ever done so, still 

 less that, failing a simpler way of attaining his object, no fox 

 could so reason. Albeit, we believe there are very few cases 

 in which a line of reason involving so many steps as that 

 suggested liy Mr. Henslow has been followed by an 

 animal. Mr. Henslow makes a good point in noting liow 

 like tho practical reasoning of animals is the reasoning of 

 young folk. " A boy the other day," he says, " found the 

 straps of his skates frozen. The fact only suggested 

 o'ltinij them. Not one of his schoolfellows reflected upon 

 tho abstract fact tliat the ice would melt if he sat upon his 

 foot a few minutes. Hence brutes and boys are exactly 

 alike in that nothing occurs to either beyond what the 

 immediate fact before them m.iy suggest The one kind I 

 call purely practical reasoning, which both have ; the 



