March 17, 1893. J 



SCIENCE. 



151 



There is no time at which the hen is so susceptible to the gallant 

 attentions of her liege lord as just at the end of this cackling 

 period. I have frequently observed this of our barnyard fowls> 

 of guinea hens, both domestic and in the wild state, and of pea- 

 fowls. In my opinion, the cackle is intended to notify the male 

 bird of the Barkiss-like condition of his mate. 



As to the case of the cac tribe, it is so common to see a mother 

 cat in the country bring field-mice, young rabbits, moles, or 

 gi-ound squirrels in to her kittens and watch their playful antics 

 with them, that the conclusions arrived at by Mr. Lees are irre- 

 sistible. This winter an intelligent house-cat, on a farm where 

 I have been studying winter life in field and woods, led me some 

 distance to where several grain-ricks had stood during the fall. 

 I soon saw that she wanted me to turn over the fence rail floor 

 that still remained there, that she might capture the field-mice 

 living beneath. This I did, while Tabby caught four mice in 

 quick succession. The first one she gulped down at a rapid rate, 

 the second she played with a little while, the third she played 

 with much longer and, half-devoured, left to her eldest son, a 

 full-grown Tom who had accompanied us, and the fourth she 

 barely wounded and also turned over to his tender mercies. In 

 a word, while hunger was a dormant passion, she quickly de- 

 voured her prey, after that her instinctive disposition to practise 

 and keep perfect the arts whereby such elusive game is captured 

 was paramount. 



Mr. Slater is in error in thinking that a comparatively few now 

 possess the power to "wag the ear." This power is common 

 among the West Indian half-breeds and the Maya and other de- 

 rivatives of Mexico and Central America, and many whites have 

 the power who hardly realize the fact. It is not uncommon to 

 observe this if one will suddenly say to a companion, "What 

 was that noise ? " If Mr. Slater will say this in a semi-slartled 

 way, he will notice that in no inconsiderable number of cases 

 there, will be a slight instinctive movement of the muscles in 

 question, more or less pronounced. Nor is the ear that Darwin 

 illustrates in his " Descent of Man " as being allied to the pointed 

 type beloDging to our Simian relatives as uncommon as many 

 may imagine. It is my observation that this peculiarity of the 

 fold in question is oftenest to be observed in women, and in many 

 of these cases the persistence of the wisdom teeth is also a char- 

 acteristic. I have in mind two cases of this sort, one of a man, 

 the other of a woman, both residents of one of our leading cities, 

 and their social and intellectual forces. The latter is a remarka- 

 ble reversion to an earlier type, in ear, in teeth, in length of arm, 

 in painless childbirth, in flexibility of hand-joints, and in other 

 marked characteristics. It appears to me that the ear, like the 

 vermiform appendix, the suspension of the viscera, the position 

 of the orifice to the bladder, and the unprotected condition of 

 certain niiin arteries, is yet in a transitiopal state, and not fully 

 adapted to the newer human conditions imposed by the erect 

 position and the artificialities of civilization. 



Eugene Murray Aaron. 



Philadelphia, March 6. 



BOOK-EEVIEWS. 



Die Zakunft des Sllbers. By Eduaed Suess. Vienna and Leipsic, 

 Braumiiller. 1893 327 p. 



Dr. Suess is eminent as a geologist, and it would be imperti- 

 nent on the part of the present writer to attempt a ciiticism, or 

 even an exposition, of his views on the geological and metallur- 

 gical conditions which aflfect the production of the precious 

 metals. Dr. Suess's conclusions are similar to those which he 

 gave to the world some fifteen years ago, in his monograph on 

 the " Future of Gold," published in 1877. He believes that the 

 production of gold is likely to be limited in the future, and will 

 not supply sufficient gold to meet the monetary consumption and 

 the consumption in the arts. He believes also that the produc- 

 tion of silver will not progress as rapidly, or that its depreciation 

 will descend as far, as is often supposed. He believes that gold 

 must eventually cease to be used as a standard of value; while 

 the production of silver is likely to continue at a comparatively 

 equable pace, making that metal eventually the basis of the 



world's money. Icitprnational bimetallism, even if it were 

 practicable, would be only a half-way measure, paving the way 

 to the ultimate adoption of the single silver standard. 



To this line of reasoning, the economist who, like the present 

 writer, believes that the gold standard works to reasonable satis- 

 faction, would answer in some such fashion as this. If it were 

 true that all exchanges were effected by the actual use of coined 

 money, undoubtedly the monetary supply of gold would not suf- 

 fice, at the present range of prices; and on that supposition the 

 maintenance of the gold standard must be accompanied by a fall 

 in prices, which would in many ways be distressing. But the 

 fact is that in modern communities gold is used but to an insig- 

 niScent extent as a medium of exchange. The great bulk of the 

 exchanges are effected by credit substitutes of various sorts. 

 Much the most effective of these is the modem machinery of 

 banking, by means of which, especially in countries like the 

 United States and England, an enormous volume of transactions 

 is settled with an insigniScant use of coin. So far as retail trans- 

 actions are concerned, bank notes, government notes, silver as a 

 subsidiary coin, do the greater part of the money work in all 

 civilized communities. Gold, therefore, acts in the main simply 

 as a measure of value or a standard of value; something in terms 

 of which the values of commodities are expressed, and into which 

 all other forma of currency are convertible. It performs its- 

 function very largely by being held as a reserve in the great cen- 

 tral depositaries, serving simply to sustain and regulate the cir- 

 culating medium. The evidence does not indicate that the supply 

 of gold is insufficient for this purpose. On the contrary, large 

 accumulations of gold have been made in recent years by 

 civilized countries; by Germany in 1873, by the United 

 States in 1879, by Italy in 1883, by Austria in 1893-3, without 

 causing, in the opinion of the present writer, any appreciable 

 difficulties. It is not impossible that in the distant future the 

 supply of gold will prove insufficient, and that some change may 

 be made by the great civilized countries in their standard of 

 value. But such a change for the visible future is highly im- 

 probable. The drift of the time is toward the gold standard in 

 all the great countries; with a constant development and use of 

 credit substitutes, but with gold as the sole basis. So far as we 

 can see into the future, this policy will work no harm, and will 

 conduce greatly to stability and convenience in the circulating 

 medium. 



So far as silver is concerned, it is undoubtedly true that the 

 method of occurrence of silver ores makes it probable that each 

 individual find will soon be exhausted. The great bonan- 

 zas, of which the Comstock lode was the first in the United 

 States, have soon given out, and the great and rapid increase in 

 the production of silver has been due to successive lucky finds. 

 Geologically speaking, therefore, the enormous increase in pro- 

 duction, which has taken place in the last twenty-five years, may 

 be regarded as temporary. But historically speaking, it is im- 

 possible to say that these finds will not continue for a period of 

 great length in human history. The hard fact is that the pro- 

 duction of silver has increased with extraordinary rapidity in 

 the last twenty years, and that as yet there are no signs of relaxa- 

 tion. If this process continues, the decline in the value of siher 

 cannot be checked. If it ceases, the price of silver in terms of 

 gold is likely, at best, to remain where it now is. In either case, 

 there is no ground for supposing that silver will come to be used 

 on the same terms as gold by civilized nations, still less that it is 

 likely to displace gold, as Dr. Suess predicts. 



F. W. Taussig. 



Harvard University, Cambridge, Mass. 



How to Manage the Dynamo. By S. R. Bottone. New York, 

 Macmillan & Co. 



This little book is meant, as its author tells us, for steam engi- 

 neers who are called upon to take care of dynamos, without hav- 

 ing any previous training or knowledge. As this class is a rather 

 large one, there is no doubt but that there will be a considerable 

 demand. 



The book is very clearly written, and contains just about all 

 that the men for whose benefit the author is writing will require 



