404 



NATURE 



[February 21, 1901 



on the roads. Mr. G. L. O. Davidson's name has also recently 

 figured in several papers in connection with the problem of 

 artificial flight, and illustrations of one of his models appear in 

 the Scientific American for February 2. The model in question 

 is a bird-shaped glider, the tail of which has movable parts 

 provided with automatic mechanism for regulating the balance 

 and stability. It appears to have glided satisfactorily, but we 

 do not gather from the journal in question that Mr. Davidson 

 has himself performed glides through the air or experimented 

 with motor-driven models. M. Santos Dumont has been ex- 

 perimenting with a motor-propelled balloon, weighing altogether 

 not more than 250 pounds ; but the only performance of which 

 we have read consisted in the maintenance of a relative velocity 

 of seven miles an hour for half a minute. 



During a severe sleet-storm over a large tract of the northern 

 United States, including Missouri, the water froze as it fell, 

 forming such a heavy coating of ice upon the trees that many of 

 them were bent to the ground by the load, as shown in the 

 accompanying illustration from a paper by Dr. H. von Schrenk, 

 in the Transactions of the Academy of Science of St. Louis. 

 The tree in the foreground is a soft maple {Acer dasycarpum), 

 likewise the row of trees of which it is one. The trees at the 

 left are birches [Beitda alba). The tops of the maples scraped 

 on the snow of the street, and is was impossible for one person 

 to lift the top of a tree, much less to restore it to its original 

 position. These trees are good instances of the appearance ot 

 the trees all over the affected area ; they remained in the bent 



position until the ice melted a week later, when the maples 

 returned nearly to their original position and the birches stood 

 quite upright as they were before the storm. Dr. Schrenk 

 weighed about two hundred branches, taken from various trees, 

 and he found that the ice-coated branches of the maples were 

 nearly ten times heavier than the same branches without the 

 layer of frozen water upon it. When the branches bore icicles 

 the ratio was much greater, in many cases the weight being 

 about thirty times greater than that of the branches without ice. 



Dr. E. Leyst has published in the Bulletin of the Imperial 

 Society of Naturalists of Moscow an elaborate discussion of the 

 I'aily range of barometric pressure at that place deduced from 

 liourly observations, and has compared the results with those 

 obtained from earlier observations and with observations made 

 at St. Petersburg. The values of the harmonic analysis coincide 

 generally with those deduced in the laborious discussions of Dr. 

 Buchan and Dr. Hann. One of the important points of the 

 discussion is the conclusion that the daily range at Moscow 

 appears to have undergone a secular change in so far that the 

 extremes of the daily curve occur earlier than was the case 

 some thirty or thirty-five years ago. 



The vitality of certain micro-organisms, both pathogenic and 

 otherwise, in milk under various conditions, forms the subject of 

 an elaborate memoir by Messrs. F. Valagussa and C. Ortona, of 

 the Hygienic Institute of the University of Rome, published in 



NO. 1634. VOL. 63] 



the Annali d^Igiene Sperifnentale. The action of sunlight on 

 bacteria in milk was investigated, and, as was only to be ex- 

 pected, in consequence of the opacity of the liquid no deleterious 

 effect was detected, except in. the case of those varieties which 

 live on the surface of liquids and were, therefore, not shielded 

 from the bactericidal action of sunshine. Another point of 

 interest investigated was the effect of its inoculation into milk 

 upon the elaboration of toxins by the diphtheria bacillus. It wa& 

 found that although this bacillus does produce toxin when grow- 

 ing in milk, its strength is less than when grown in other culture- 

 media ; moreover, a marked increase in the strength of the toxin 

 was noted when the cultivations were kept in a cool cellar 

 instead of at the ordinary temperature of the laboratory. The 

 exact thermal death-point of the tubercle bacillus in milk was alsa 

 reinvestigated, this being a matter on which many different 

 opinions are held. The authors state that exposure to a temper- 

 ature of 60°, 70° and So° C. is insufficient to guarantee the de- 

 struction of this bacillus in milk. Milk freshly drawn from the 

 cow, with precautions ensuring its sterility, was found to afford a 

 better culture material for bacteria than after it had been arti- 

 ficially sterilised by heating to 100° C. The paper is rendered 

 of additional value by the very carefully compiled bibliography 

 of the existing literature on the subject which is appended, and 

 which makes it of special use to all interested in this section of 

 dairy-bacteriology. 



A PAPER on hermit-crabs allied to Pagurus bernhardus, by 

 Mr. J. E. Benedict, is published in vol. xxiii. (pp. 451-466) of 

 the Proceedings of the U.S. Museum, and is noteworthy on ac- 

 count of the excellence of the illustrations. Many of the forms- 

 described are closely related, but, in the absence of intergrada- 

 tion, they are classed as species rather than races. 



Bulletin No. 14 of the Biological Division of the U.S- 

 Department of Agriculture is devoted to a digest of the laws 

 regulating the sale and transport of game in the different States 

 of the union, the authors being Messrs. T. S. Palmer and H. W. 

 Olds. All the States, it appears, are now , fully convinced 

 that unless stringent regulations are put in force the game 

 animals and birds of America will ere long disappear for ever. 

 It is satisfactory to learn that every State has now established 

 laws bearing upon the preservation of game, although more 

 general harmony between them might be advantageous. In- 

 their preface the authors state that an Act of Congress passed in 

 May last supplements previous laws by prohibiting the shipment 

 from one State to another of birds killed in violation of local- 

 laws, and by subjecting birds brought into any State to the 

 regulations affecting native-raised specimens. The need of a 

 compilation epitomising and contrasting the various laws and 

 regulations has been much felt, and this want the present 

 pamphlet endeavours to supply. 



The first three numbers of the new volume of I>ie Natur 

 contain a full report of a lecture delivered in November last 

 before the Verein zur Verbreitung naturwissentschaftlicher 

 Kenntnisse in Vienna, by Prof. F. Toula, on the geological 

 history of the Black Sea. The succession of events, beginning 

 doubtfully in the lower or middle Oligocene, and with cer- 

 tainty in the uppermost Oligocene, is traced through nine 

 distinct stages. The paper forms a most useful summary of 

 recent research over an area including much of the eastern 

 Mediterranean, and extending northward and eastward into 

 Russia and Siberia ; a considerable proportion of the work, 

 especially that of Russian geologists and hydrographers, being, 

 not easily accessible. 



According to the American Museum Journal for December 

 the search for fossil vertebrate remains in the far West is being 

 prosecuted with as much activity as ever. Fourteen large cases of 



