66 



NATURE 



[May 27, 1875 



and sulphate of copper. Ttie substances sometimes 

 employed to colour sweetmeats, liqueurs, jellies, &c., 

 include some of the most fatal poisons, such as the 

 acetate, arsenite, and carbonate of copper, chromate and 

 iodide of lead, and the sulphides of arsenic and mercury. 

 Indeed, we well remember going over a sweetmeat manu- 

 factory, and on remarking on the bright yellow colour of 

 some large comfits we were told that chrome yellow was 

 employed to produce it, our informant evidently having 

 no idea that the substance is a most virulent poison. A 

 long article is devoted to the adulteration and fabrication 

 of wines, and the "plastering" and "fortifying" of 

 sherries is discussed at length. In all cases the most 

 recent results are given, and the work is well edited 

 and carefully written. A glossary at the end of the book 

 will be found useful both to the analyst and the student. 



LETTERS TO THE EDITOR 



[ The Editor does not hold himself responsible Jor opinions expressed 

 by his correspondents. Neither can he undertake to return, 

 or to correspond with the writers of, rejected manuscripts. 

 No notice is taken of anonymous communications.'^ 



"The Unseen Universe" 



We have read with satisfaction (Nature, vol. xii. p. 41), your 

 very candid and fair /r/m of our recent woik, "The Unseen 

 Universe." There are, however, one or two comments added 

 in which the writer seems to have misapprehended our meaning, 

 possibly from the fact that in the first edition of such a work the 

 arrangement may be regarded as not having quite taken its final 

 shape. 



To begin, we fail to understand what the reviewer means when 

 he says, " It is a mere theological dogma to say that what energy 

 perishes in the visible passes into the invisible universe ; and the 

 dogma is worthless as a physical principle on which to build any 

 physical reasoning." 



Oar views will be found on p. 159 of our book : "May we not 

 say that when energy is carritd from matter into ether it is carried 

 from the visible into the invisible?^' Surely the ether may be 

 looked upon as forming part of the invisible universe, and also 

 as having received a large portion of the energy which was once 

 attached to visible matter. 



Our object was to show that we introduced no new dogma 

 inconsistent with the received ideas regarding energy, inasmuch 

 as these contemplate an invisible universe as truly as we our- 

 selves do. 



The second point upon which we would remark is the asser- 

 tion of the reviewer that by regarding the visible universe as an 

 infinite whole, the arguments on which its end and its beginning 

 are inferred seem to vanish. In reply to this we would remark, 

 that even allowing (which we are not disposed to allow) that the 

 visible universe is infinite, this would not affect our argument 

 against its past eternity. Our argument (see p. 127 of the book) 

 is, that the dissipation of the energy of the visible universe proceeds, 

 pari passu, rvith the aggregation of mass, and the very fact there- 

 tore that the large masses of the universe are of finite lize is suffi- 

 cient to assztre us that the process cannot have been going on for 

 ever. 



The Authors of "The Unseen Universe." 



Sense of Humour and Reason in Animals 

 In the recently published edition of the " Descent of Man" 

 there is some additional matter concerning the above subjects, and 

 as the following illustrative cases fell under my own observation, I 

 think it is worth while to publish them as supplementary to those 

 adduced by Mr. Darwin. 



Several years ago I used to watch carefully the young Orang 

 Outang at the Zoological Gardens, and I am quite sure that she 

 manitesttd a stns-e ot the ludicrous. One example will suffice. 

 Her feeding-tin was ot a somewhat peculiar shape, and when it 

 was empty she used sometimes to invert it upon her head. The 

 tin then presented a comical resemblance to a bonnet, and as its 

 wearer would generally favour the spectators with a broad grin 

 at the time of putting it on, she never failed to raise a laugh from 

 them. Her success in this respect was evidently attended with 

 no small gratification on her part. 



I once had a Skye terrier which, like all of his kind, was very 

 intelligent. When in good humour he had several tricks, which 

 I know to have been self-taught, and the sole object of which 

 was evidently to excite laughter. For instance, while lying upon 

 one side and violently grinning,* he would hold one leg in his 

 mouth. Under such circumstances nothing pleased him so much 

 as having his joke duly appreciated, while if no notice was taken 

 of him he would become sulky. On the other hand, nothing 

 that could happen displeased him so much as being laughed at 

 when he did not intend to be ridiculous. Mr. Darwin says : — 

 " Several observers have stated that monkeys certainly dislike 

 being laughed at " (p. 71). There can be little or no doubt that 

 this is true of monkeys ; but I never knew of a re?lly good case 

 among dogs save this one, and here the signs of dislike were un- 

 equivocal. To give one instance. He used to be very fond of 

 catching flies upon the window-panes, and if ridiculed when un- 

 successful, was evidently much annoyed. On one occasion, in order 

 to see what he would do, I purposely laughed immoderately every 

 time he failed. It so happened that he did so several times in 

 succession— partly, I believe, in consequence of my laughing — 

 and eventually he became so distressed that he T^o?,\Vi\t\y pretended 

 to catch the fly, going through all the appropriate actions with 

 his lips and tongue, and afterwards rubbing the ground with his 

 neck as if to kill the victim : he then looked up at me with a 

 triumphant air of success. So well was the whole process simu- 

 lated, that I should have been quite deceived, had I not seen 

 that the fly was still upon the window. Accordingly I drew his 

 attention to t^is fact, as well as to the absence of anything upon 

 the floor ; and when he saw that his hypocrisy had been detected, 

 he slunk away under some furniture, evidently very much 

 ashamed of himself. 



The following example of reason in a dog is the most striking 

 that has ever fallen wittiin my personal observation. A son of 

 the above-mentioned terrier followed a conveyance from the 

 house at which I resided in the country, to a town ten miles 

 distant. He only did this on one occasion, and about five months 

 afterwards was taken by traiji to the same town as a present to 

 some friends there. Shortly afterwards I called upon these 

 friends in a different conveyance from the one which the dog 

 had previously followed ; but the latter may have known that the 

 two conveyances belonged to the same house. Anyhow, after I 

 had put up the horses at an inn, I spent the morning with the 

 terrier and his new masters, and in the afternoon was accom- 

 panied by them to the inn. I should have mentioned that the 

 inn was the same as that at which the conveyance had been put 

 up on the pievious occasion, five months before. Now, the dog 

 evidently remembered this, and, reasoning from analogy, 

 inferred that I was about to return. This is shown by 

 the fact that he stole away from our party — although at what 

 precise moment he did so I cannot say, but it was certainly 

 after we had arrived at the inn ; for subsequently we all remem- 

 bered his having entered the coffee-room with us. Now, not 

 only did he infer from a single precedent that I was going home, 

 and make up his mind to go with me ; but he also further 

 reasoned thus: — "As my previous master lately sent me to 

 town, it is probable that he does not ,want me to return with 

 him to the country : therefore, if I am to seize this opportunity 

 of resuming my poaching life, I must now steal a march upon 

 the conveyance. But not only so, my former master may pos- 

 sibly pick me up and return with me to my proper owners : 

 therefore I must take care only to intercept the conveyance at a 

 point sufficiently far without the town, to make sure that he will 

 not think it worth his while to go back with me." Complicated 

 as this train of reasoning is, it is the simplest one I can devise 

 to account for the fact, that slightly beyond the third milestone 

 the terrier was awaiting me — lying right in the middle of the 

 road with his face towards the town. I should add that the 



* This habit of violently grinning is not, I believe, uncommon among Skye 

 terriers— the pure original breed ol Skyes, I mean, and not the broad-nosed 

 shaggy-coated animals which have almost supplanted them. The habit is 

 very remarkable, for there can be no doubt, 1 think, that it is intended to 

 imitate laughter. Manyintelhgent dogs understand the meaning of laughter 

 as implying good humour. I have a setter just now, which always rouses 

 up and whines for admittance to a room when he hears a good laugh going 

 on, wagging his tail the while, in proportion to the varying intensity of the 

 laughter ; but I do not know of any other breed of clogs which actually imitates 

 it- at all events not with such evident purpose as do bkye terriers. The 

 purpose is evident, not only because the gesture is never made at any other 

 time than when the animal wishes to be particularly agreeable ; but iXio 

 because the grin is carried to a highly unnatural degree— much more, e.g., 

 than the strongest snarl would require ; and, which is stranger still, I have 

 frequently seen my terrier on such occasions shaking his sides in a con- 

 vulsive manner— an action he never performed at any other time. 



