lOG 



♦ KNOWLEDGE ♦ 



[Aug. 8, 1884. 



mouth and stomach. The very first thing we want to 

 know about any substance which we think of swallowing 

 is whether it is immediately destructive of the bodily 

 tissues. Now, the nerves of touch distributed to the tip of 

 the tongue instantly inform us on this important primary 

 question. In tasting an unknown substance, indeed, 

 we all of us instinctively try it beforehand by 

 touching it very lightly with the tip of the 

 tongue. If it is caustic, like vitriol, or pungent, 

 like cayenne and mustard, or fiery, like spirits of 

 wine, or warping, like borax or alum, the tip of the 

 tongue instantaneously warns us that it is not a fitting 

 substance to be swallowed wholesale. This chemical 

 sensibility of the nerves of the tongue is only a modified 

 form of the general chemical sensibility of the whole body. 

 Mustard, made into a plaster, acts on the skin very 

 much as it acts on the tongue, only less rapidly and loss 

 specifically. The warping effect of alkalies can be felt 

 on any ])art of the body, and the fiery character of alcohol 

 faintly affects the nerves of touch in the same manner as 

 the ncrvi's of taste. In .short, the sen.sitiveness of the 

 tongue in this respect is only an intensified form of the 

 common sensitiveness of nerves generally. 



When a substance has passed the first examination with 

 the tip of the tongue, and has been pronounced harmless, 

 it is handed over to the middle region, supplied with the 

 nerves of taste proper. It is the special function of these 

 nerves to discriminate between sweet and bitter objects, as 

 well as between various tasty substances which we know 

 distinctively as flavours. On the whole, it is clear that 

 human beings like .°weets, that the tongue responds favour- 

 ably to the class of foods which contain sugar as a principal 

 element. The reason for this strongly-marked prefer- 

 ence is probably to be found in the ancestral fruit-eating 

 habits of our race. To our early arboreal progenitors fruits 

 were, of course, almost the only sweet objects known ; they 

 had as yet no .sugar factories, and they doubtless seldom 

 tasted even honey in the honey-comb. Hence it was natural 

 that the presence of sugar should come to be the instinctive 

 test, as it were, for the edibility of whatever object they 

 happened to come across. In our modern artificial con- 

 dition, where we use sugar to excess, and often in too con- 

 centrated forms, taste alone no longer acts as a safe guide ; 

 as children we eat too many sweetmeats, and in adult life 

 we have no digestions : but that is only because we have 

 altered the natural conditions, and have separated the sugar 

 from the other wholesome food with which it is usually 

 combined under its original circumstances. On the other 

 hand, almost all bitter substances in the vegetable world 

 are known to be poisonous, and our repugnance to bitter 

 tastes is thus due to the registered experience of countless 

 generations of early human or pra>-!iuman ancestors. 



The third and lowest region of the tongue is the one 

 cognisant of pleasures and pains in immediate sympathy 

 with the stomach. The feelings we experience in this part 

 ■ of our throats can scarcely be properly described as tastes ; 

 they are best characterised, in Professor Bain's well-chosen 

 language, as Kelishcs and Disgusts. When we have begun 

 to chew a piece of wholesome beef-.steak in healthy hunger, 

 we are conscious of a certain pleasurable sensation as it 

 reaches the back of the tongue which induces us to persevere 

 with the action of swallowing, and finally commit it to the 

 digestive apparatus. On the other hand, when we take a 

 dose of codliver oil, we are conscious, at the same stage in 

 the proceedings, of a certain physical repulsion to the act of 

 swallowing it ; something seems to rise up instinctively 

 in the throat which warns us that cod-liver oil is a 

 remarkably difliouli substance to digest and assimilate. 

 The sensations thus experienced are purely premonitory of 



the eflfect of the food taken upon the stomach. Accord- 

 ingly, they vary much, according to our state of health or 

 appetite. However seasick we may be, ])ungent things are 

 still pungent to u.s, acid thicigs acid, bitter things bitter, 

 and sweet things sweet. But meat, fat, oils, and so forth, 

 produce effects very different from their ordinary results. 

 The tastes discriminated by the lower part of the tongue 

 are all of this character ; and the thiugs which find it most 

 difficult to pass the final examination liere are tainted or 

 putrid meats, very rich or buttery dishes, and other indi- 

 gestible or bilious substances. 



Thus we may say roughly that the threshold of the 

 mouth warns us against whatever will prove absolutely 

 destructive to the tissues generally ; the central region dis- 

 tinguishes between what is ordinary human food, and what 

 is poisonous or otherwise deleterious when taken internally; 

 and the lower portion of the tongue and thrr at pronounces 

 finally upon the digestibility and fitness for the stomach 

 (in its passing condition) of the food which has success- 

 fully passed the two earlier preliminary examinations. 



THE ORIGIN OF SILK. 



IF we put any trust in tradition, says an English journal, 

 there is a legend that Tchin, the eldest son of Japhet, 

 father of the Asiatic race, taught his children the art of 

 ))reparing silk, as well as the arts of painting and sculp- 

 ture. Be this as it may, it is certain that, about 3,000 

 years before the Christian era, a Chinese book, the " Ghou- 

 Kiug," described silken cords, which were stretched upon a 

 musical instrument invented by the Emperor Fo-HL One 

 of his successors. Chin Nong, reputed inventor of the 

 plough, explained to his contemporaries what beautiful 

 stuff's could be obtained by cultivation of the mulberry tree, 

 and about the year B.C. 2600 an empress, to whom a 

 grateful posterity assigned a place in a celestial constella- 

 tion, perfected the art of unravelling the cocoon and 

 weaving. From that time silk culture had its principal 

 seat near the northern portion of the Yellow River, in the 

 province of Chan-Tong. There was produced silk for the 

 Royal household. Yellow was the chosen colour for the 

 emperor, empress, and prince imperial ; violet for the 

 other wires of the emperor, blue for distinguished officers, 

 red for those less conspicuous, and black for everyone else. 

 In the book of rites, " Li-Ki," the ceremonies performed at 

 the harvest are carefully described. Even the empress did 

 not disdain to gather the leaves of the mulberry with her 

 own dainty fingers, and watched over the rearing of the 

 busy toilers of the cocoon. 



For a long time this invaluable industry remained the 

 exclusive property of the Chinese empire, but about the 

 third century before the Christian era a military expedition 

 from China bore the results of its civilisation to the startled 

 Occident. Silk became known in Persia and India, and 

 was at last brought to Europe. The soldiers of Crassus, 

 B.C. .56, saw silken standards among the Parthians, and a 

 few years later an immense velarium of silk protected the 

 spectators in the Roman circus from the rays of the sun. 

 From this time the Romans were always provided with the 

 beautiful textures which were the admiration of their 

 legions. Yet silk was still the privileged possession of the 

 rich, and in the time of Aurelian, who flourished in the 

 third century, was worth about forty times its present 

 value. The enormous price, when considered with the fact 

 that there was at that time no commerce between Rome 

 and the Orient, goes far towards explaining the great 

 hoarding of treasure and jewellery which has since that 

 time gone on in India. 



