220 



SCIENCE. 



[Vol. I., No. 8. 



Japanese in Yezo, which, making the usual allowance 

 foi' official exagi^eration in matters of this kind, must 

 probably be reduced to about 80,000. Be tliis as it 

 may, it is certain that the fertile island of Yezo, 

 which is appreciated in a certain way by the Japanese, 

 but which is very irrationally and imperfectly utilized, 

 is very thinly populated. Tlie island has an area of 

 nearly 80,000 D kilometi-es, and a population of only 

 about two to the square kilometre. 



The Ainos — whose unsophisticated artlessness, love 

 of truth, peaceful disposition, hospitality, and discreet, 

 modest, and sober deportment, by contrast with other 

 orientals, strike one all the more agreeably — show, 

 iu Iheir short but well-proportioned body, thick and 

 beautiful hair, and physiognomy, particularly iu the 

 deep-set eyes, unmistakable agreements with people 

 of more western countries, say, central Asia. In 

 language, as well as customs and traditions, they are 

 decidedly strangers to tlie Japanese; but, so peaceful 

 are they, they submit freely to the yoke that has been 

 placed upon them, without ever plotting mischief. 

 Whether for them, as well as for the rich natural 

 advantages of the island of Yezo, a colonization in 

 European fashion would be a great benefit in com- 

 parison with that of tlie Japanese, who have much 

 to learn and much to do for a long time to come in 

 their own country, may here be left undecided. 

 However, such a wish will certainly appear natural 

 to all those who have gained a more intimate acquaint- 

 ance with the island of Yezo and its inhabitants. 



INFLUENCE OF THE VAGUS NERVE 

 UPON THE HEART. 



In continuati(m of his studies upon the physiology 

 of the frog's heart, Lowit confirms' Gaskell's discov- 

 ery, that in normal diastole the cardiac muscle is not 

 completely relaxed, but in a state of sliglit tonic 

 contraction: this, Luwit finds, is abolislieil during 

 vagus inhibition. The powerful beats which usually 

 follow a period of inhibition must be due to some 

 change in the heart-muscle, and not in its motor- 

 nerve centres; for Kroneeker has proved that every 

 cardiac contraction is maximal. Their cause Liiwit 

 finds in the more complete diastolic expansion ; and 

 he also explains similarly the more vigorous pulsa- 

 tions sometimes seen during a vagus stimulation not 

 powerful enough to alter the heart's rate of beat. 

 He confirms Schiff's usually ignored discovery, that 

 stimulating the pneumogastric sometimes quickens 

 the pulse; but, after a careful study of the circunr- 

 stances \inder which this plienomenon occurs, he 

 rejects Schiff's hypothesis, that the vagus contains 

 only one set of heart nerve-fibres, whose action varies 

 with degree of stimulation, etc. We must .assume 

 twodistinct sets of fibres, — acardio-accelerator and a 

 cardio-inbibitory : the latter are more irritable, but 

 more easily injured, bearing thus the same relation- 

 ship to the accelerator fibres as do the vaso-constric- 

 tory nerves to the vaso-dilator, according to Goltz. 

 By exposing the frog's vagus to the action of sub- 

 stances, as nitre, which are known to diminish nerve 

 irritability, one can turn the vagus into a pulse- 

 quickening nerve: on washing out the nitre, it again 

 becomes pulse-slowing; and so, back and forth, 

 several limes, until death-changes commence. In 

 mammalia the phenomenon cannot be i-eproduced 

 with the same certainty; but occasionally one can 

 succeed in getting the vagus into a condition in 

 which its inhibitory fibres are not irritable, while 

 the accelerator are. During vagus acceleration the 



frog's ventricle becomes paler, indicating a con- 

 tracted condition of its musculature even in diastole. 

 This abnormal state of tonic contraction is not the 

 cause of the acceleration, for the pallor may precede 

 the pulse-quickening, or last after it; and weak stim- 

 uli sometimes cause acceleration with no pallor. 

 The small pulsations usually seen during the accel- 

 eration are due to the increased tonicity of the lieart- 

 muscle usually present at the same time, and pre- 

 venting diastolic relaxation of normal extent. The 

 accelerator fibres probably act on motor-nerve centres 

 in the heart, arousing pi'ocesses, which, when feeble, 

 merely alter the rate of beat ; when more powerful, 

 also increase the tonus of the heart-muscle. 



H. Newell Maktin. 



THE EXTINCT LAKE AGASSIZ. 



In the recently published Tenth .annual report of 

 the geological and natural-history survey of Minneso- 

 ta, for 1881, Prof. N. H. Winchell gives an abstract 

 (p. 5) of Mr. Warren Upham's observations on the 

 shore-lines of the great sheet of water that once flood- 

 ed the valley of the Red River of the North, and over- 

 flowed southward into the Minnesota. "The lake 

 had three stationary periods, forming throe beaches. 

 They all ascend above a given datum level toward the 

 north, the rate increasing in going toward the north. 

 The highest beach-line ascends 125 feet in about 150 

 miles. Hie beach being one continuous shore-line. 

 The northern portion of the lake fell at intervals 

 from this high beach-line, . . . while the water-level 

 in the extreme southern part stood nearly stationary, 

 the northern fractional beaches converging into one 

 toward the southern extremity of the lake. The next 

 distinct beach, found in the southern part of the re- 

 gion, ascends toward the north 70 feet in 150 miles. 

 . . . The fall of the lake had therefoi-e been sixty 

 feet more at the northern than at the southern end. 

 . . . The third beach-line, formed when the outlet 

 had been excavated to the level of Lake Traverse, is 

 known along a distance of 1:55 miles; .and. its north- 

 ward ascent was at first 50 feet, and after\vards only 

 about 25 feet. . . . The fall of L.ake Agassiz from 

 the highest beach level to the third at Lake Traverse 

 Wiis about SO feet, and, in the vicinity of Maple Lake, 

 165 feet. . . . These phenomena seem inconsistent 

 with that hypothesis which supposes an elevation of 

 northern land as a barrier to contain this vast inland 

 lake, inasmuch as these beaches would have to pre- 

 sent a slope in the opposite direction, iu order to 

 change the outlet from L.ake Ti'averse to Hudson's 

 Bay. . . . Tliey have been ascribed to the operation 

 of the glacial period iu the epoch of its decline, when 

 the ice still existed toward the north as a barrier to 

 prevent northern drainage; . . . .and in the opinion 

 of Mr. Upham, its attraction was sufficient to move 

 the mass of water toward itself, and to cause an 

 ascending shore-lino in that direction. . . . Lake 

 Agassiz probably covered Red Lake under 50 or 100 

 feet of water above its present level. Lake of the 

 Woods under about 200 feet, the Red River Valley at 

 St. Vincent 450 feet, and Lake Winnipeg about 600 

 feet." Tlie area thus flooded is much larger than 

 heretofore supposed. 



' PflUgc 



i archiv, xxix. 



LETTERS TO THE EDITOR. 

 Movement of the arras in vsralking. 



It seems to me I can best lay this ghost of our ani- 

 mal origin by drawing attention to the fact that the 

 swinging of any part that is sufficiently free may be 



