52 



SCIENCE. 



[N. S. Vol. XXIV. No. 602. 



valley of the Missouri in Iowa a bed of coal, 

 similar in all respects to this one, occurs, and 

 is probably a part of the same bed. The evi- 

 dence from deep wells at Omaha, Nebraska 

 City, Beatrice and Lincoln, the last named 

 well being 2,463 feet deep, points to beds of 

 coal but a few inches in thickness and thin- 

 ning rapidly to the westward. 



For a number of years coal has been mined 

 in various places in the southeastern, or 

 carboniferous portion of this state, as at 

 Nebraska City, Kulo, South Fork and else- 

 where, but the thickness of coal in each case 

 scarcely equaled eighteen inches and there 

 was no profit in mining such coal. The best 

 efforts of a Lincoln company headed by Mr. 

 Bullock, a man of ability and experience, 

 failed to make the mine at Kulo profitable, 

 and the undertaking, like that of others, was 

 abandoned at the end of two years as un- 

 profitable. 



Although considerable amounts of coal 

 were furnished at one time by the South Fork 

 Mine to the neighboring towns. Table Eock, 

 Humboldt, Salem, Dawson and Seneca, the 

 bulk of coal mined thus far has been used by 

 those mining it. Farmers and others often 

 dig out their own supply of winter fuel. A 

 vigorous effort was made to develop a bed, 

 said to be eighteen inches thick, in north- 

 eastern Nebraska, it being a lignitic coal in 

 the Cretaceous and in no way related to the 

 coal recently discovered. Simultaneously 

 with the discovery of coal at Peru come re- 

 ports not yet verified of a bed equally thick 

 at Falls City. It has certainly been the 

 opinion of geologists at large that commercial 

 coal was not to be expected in Nebraska, and 

 the occurrence of a workable bed in Peru does 

 not materially change this opinion, for at the 

 best it must be local, as shown by surround- 

 ing deep wells. Though limited to a square 

 mile or so it is of importance to this com- 

 monwealth. 



The owner of the land on which the bed of 

 coal was found leased the mine at the rate of 

 fifty cents on every ton of coal sold for three 

 dollars, and one dollar on every ton sold at 



four dollars, which may be an item of inter- 

 est to those regularly engaged in mining. 

 Erwin H. Barbour. 

 The Univebsity of Nebbaska, Lincoln, 

 April 5, 1906. 



THE RELATION OP PRESSURE IN THE CORONARY 

 VESSELS TO THE ACTIVITY OF THE ISO- 

 LATED HEART, AND SOME CLOSELY 

 RELATED PROBLEMS.^ 



The data recorded in this note were ob- 

 tained in a series of experiments on the ex- 

 cised hearts of turtles, and on the hearts of 

 guinea-pigs, rabbits, cats and dogs, both ex- 

 cised and in situ. The object was to study 

 the effect of various artificial nutrient solu- 

 tions under different conditions of tempera- 

 ture and pressure with a view of determining 

 their efficiency in restoring cardiac activity. 

 By efficiency is meant the capability of the 

 heart of maintaining an adequate blood pres- 

 sure. 



Defibrinated blood, blood dilutions, Locke's, 

 Ringer's, Howell and Greene's two solutions, 

 0.9 per cent, sodium chloride, paraffin oil and 

 hydrogen gas were employed. 



The animals were etherized and rapidly bled 

 to death, and the blood collected and defibrin- 

 ated. In isolated preparations, the hearts 

 were rapidly removed and suspended by the 

 base. Cannulse were inserted and the peri- 

 cardium removed. Ventricular tracings were 

 made by connecting this portion of the heart 

 to a simple lever which recorded the contrac- 

 tions on a drum. Auricular tracings also 

 were made in some experiments. In all cases 

 of isolated preparations, before the injection 

 was begun, the hearts were bathed in the solu- 

 tions to be employed. With all the solutions 

 except blood, or blood dilutions, oil and hydro- 

 gen, a short series of more or less rhythmical 

 contractions, similar to those evoked by sim- 

 ple mechanical stimulation, promptly followed 

 their application to the heart. In the course 

 of the experiments with the hearts in situ, a 

 constant parallelism was observed between the 

 aortic pressure and the rate of the heart. In 

 order to determine whether this result was 



^ All references to literature have been pur- 

 posely omitted. 



