330 ANNUAL OP SCIENTIFIC DISCOVERY. 



animalcules are chiefly carbon, silica, lime and iron, with traces of 

 alumina and manganese. Magnesia and other substances are only 

 present as mechanical mixtures. 



9. The quantity of iron in the minutest organisms is sometimes sur- 

 prisingly great. It is never united with the lime, but only with the 

 silica; and then rather mechanically than chemically, and as an 

 organic deposite of the metal in closed silicious cells. 



10. In consequence of the uniform and excessive development of 

 minute organic life, it exerts a great influence on other conditions of 

 the surface of the earth, and on the formation of huiiias in the valleys 

 of rivers. 



ON THE FORCES INFLUENCING THE CIRCULATION OF THE 



BLOOD. 



THE following fact brought before the British Association by Mr. 

 Wharton Jones, contains a physiological discovery of great importance. 

 In the wing of the bat, the main impulse to the circulating fluid is, as 

 in other animals, given by the heart, but in addition, Mr. Jones has 

 discovered that the walls of the veins in this animal contract rhythmi- 

 cally like those of the heart, and any regurgitation being prevented 

 by numerous and appropriately placed valves, they thus assist very 

 materially in forcing the blood onwards. The existence of this 

 rhythmical contractility in the walls of the veins is a fact new to 

 physiological science. 



THE SPIRAL .STRUCTURE OF MUSCLE, AND THE MUSCULAR 



STRUCTURE OF CILIA. 



IN the year 1842, Dr. Barry, of England, in a memoir published in 

 the transactions of the Royal Society, recorded his discovery of the 

 spiral structure of muscle. By many the truth of this statement was 

 doubted, and by some it was flatly denied. The celebrated German 

 physiologist Purkinje, however, has recently shown that not only has 

 muscle a spiral structure, but that cilia also are no other than little 

 muscles. This is a confirmation of Dr. Barry's observations made nine 

 years ago. That cilia also have a truly muscular character and struc- 

 ture is demonstrable, not only in cilia from the gill of the oyster 

 and the common sea-mussel, but in those of the Infusoria. Jameson's 

 Journal. 



ON THE ORIGIN OF SPECIES. 



MR ARTHUR HENFREY in his recent work on " The Vegetation 



l^\ 



of Europe, its conditions and causes," thus speaks of the original 

 creation of a one or a number of individuals. " Some naturalists 

 contend that the original creation must have consisted of a number of 

 individuals ; but it seems more in accordance with the simplicity of 

 nature, to suppose that a single parent or pair of parents alone was 



