174 



SCIENTIFIC NE\VS. 



[Oct. 1st, l5 



- extracts every possible particle of moisture from wood, 

 brick, or stone for its own sustenance, by means of the tiny 

 roots which work their way even into the hardest stone. 

 Of course it does ! For my own part I am heartily ashamed 

 of requiring to be told of so obvious a fact, and hope that 

 every reader of Science Gossip who has not already reasoned 

 it out for himself will be equally penitent. Every leaf of 

 every plant that grows is largely composed of water, and 

 every such leaf is continually exhaling gaseous water, and 

 this water is supplied by rootlet absorption. The ivy 

 differs from ordinary plants in having rootlets on every 

 stem, thus rendering it almost independent of its main 

 ground root. Its notorious killing action upon growing 

 trees when it takes full possession of them is mainly due to 

 absorption of their juices. If there is any juice in a stone 

 or brick wall, ic, any moisture, the ivy must have it. 

 Besides this, the ivy directly protects the wall from the 

 wetting action of raindrift. — Science Gossip. 



Experiments with a Candle. — Put a lighted candle 

 behind a bottle, pickle-jar, or any other object having 

 a polished surface, then station yourself at about twelve 

 inches from the object, so that it hides the flame of the 

 candle from you, and blow with your breath. The candle 

 will be very easily extinguished, in consequence of the 

 currents of air that you have created around the object 

 meeting near the flame. With a board or sheet of card- 

 board of the width of the bottle, extinction would be im- 

 possible. This experiment has a counterpart that has been 

 communicated to us by IVI. Harmand, of Paris. Take two 

 bottles instead of one, and place them alongside of each 

 other, so as to leave a space of half an inch between them. 

 Place the candle opposite this space, and preserving the 

 same distance as before between your mouth and the 

 candle, blow strongly against the flame. Not only will the 

 latter not be extinguished, but it will incline slightly toward 

 you, as if through the effect of suction. This phenomenon, 

 which is analogous to the preceding, is due to the fact that as 

 a portion of the air cannot pass between the bottles, it flows 

 around their exterior and returns to the operator. — Le 

 Chercheur. 



The Chemical Composition of Man. — From a chemical 

 point of view,man is composed of thirteen elements, of which 

 five are gases and eight are solids. If we consider the chemical 

 composition of a man of the average weight of 154 pounds, 

 we will find that he is composed in large part of oxygen, 

 which is in a state of extreme compression. In fact, a man 

 weighing 154 pounds contains ninety-seven pounds of oxy- 

 gen, the volume of which, at ordinary temperature, would 

 exceed 980 cubic feet. The hydrogen is much less in 

 quantity, there being less than fifteen pounds, but which, 

 in a free state, would occupy a volume of 2,800 cubic feet. 

 The three other gases are nitrogen, nearly four pounds ; 

 chlorine, about twenty-six ounces ; and fluorine, three and 

 a quarter ounces. Of the solids, carbon stands at the head 

 of the metalloids, there being forty-eight pounds. Next 

 come phosphorus, twenty-six ounces, and sulphur, three 

 and a quarter ounces. The most abundant metal is calcium, 

 more than three pounds ; next potassium, two and a half 

 ounces; sodium, two and a quarter ounces; and lastly, iron, 

 one and a quarter ounces. It is needless to say that the 

 .various combinations made by these thirteen elements are 

 almost innumerable. — Le Practicien. 



Arrangement of Museums. — The Biological and Geolo- 

 gical Sections of the British Association met together to dis- 

 cuss the question of the arrangement of museums. The 

 matter was introduced by Dr. Wood A'ard in an interesting 

 paper, in which he said that, although it might seem a 

 simple question, the arrangement of museums had occupied 



the attention of naturalists for many years. He advocated 

 the placing of recent and fossil forms of each group in near 

 proximity — say, in a series of parallel galleries adjoining 

 each other, or in parallel rows of cases. Prof. Haddon 

 said that people who visited the British and other large 

 museums always leave with sore feet and sore heads, owing 

 to the large number of specimens they were supposed 

 to study. He believed in few specimens for a public 

 museum, but there could not be too large a series for the 

 purposes of the student. Prof. Boyd-Dawkins said that in 

 the new museum of Owens College an endeavour would be 

 made to arrange the specimens in the best manner to suit 

 all wants. The discussion was continued by many leading 

 geologists, and the general conclusion seemed to be that 

 some compromise should be effected between the two 

 extreme views, and that the student of recent forms should 

 not neglect the fossils, any more than the palaeontologist 

 should ignore the knowledge gained by the observations of 

 living forms and existing phenomena. 



Multiplication of Living Beings. — Mr. Darwin has told 

 us that " There is no exception to the rule that every organic 

 being naturally increases at so high a rate that, if not 

 destroyed, the earth would soon be covered by the progeny 

 of a single pair. Even slow-breeding man has doubled in 

 twenty-five years, and, at this rate, in less than 1,000 years 

 there would literally be no standing room for his progeny." 

 If all the offspring of the elephant, the slowest breeder 

 known, survived, there would be in 750 years nearly nine- 

 teen million elephants alive, descended from the first pair. 

 If the eight or nine million eggs which the roe of a cod is 

 said to contain developed into adult codfishes, the sea would 

 quickly become a solid mass of them. So prolific is its 

 progeny after progeny, that the common housefly is com- 

 puted to produce twenty-one millions in a season ; while so 

 enormous is the laying power of the aphis, or plant-louse, 

 that the tenth brood of one parent, without adding the pro- 

 ducts of all the generations which precede the tenth, would 

 contain more ponderable matter than all the population of 

 China, estimating this at 500,000,000. It is the same with 

 plants. If an annual plant produced only two seeds yearly, 

 and all the seedlings survived and reproduced in like man- 

 ner, one million plants would be produced in twenty years 

 from the single ancestor. Should the increase be at the 

 rate of fifty seeds yearly, the result, if unchecked, would be 

 to cover the globe in nine years, leaving no room for other 

 plants. The lower organisms multiply with astonishing 

 rapidity — some minute fungi increasing a billionfold in a few 

 hours ; and the protococciis, or red snow, multiplies so fast 

 as to tinge many acres of snow with its crimson in a 

 night. 



Degeneration of the Teeth. — An article recently pub- 

 lished in an evening contemporary very properly criticises 

 the theory started in an American dental journal that vege- 

 tarian diet would, if universally adopted, produce an eden- 

 tulous condition of the jaws in the course of a few genera- 

 tions, utterly regardless of the fact that vegetarian races 

 have magnificent teeth. The pathology of this condition is 

 stated to be disuse and consequent atrophy of muscles and 

 jaws, then degeneration, and ultimately suppression of the 

 teeth entirely. That comparatively little employment of 

 teeth has something to do with their degeneration in civi- 

 lised nations admits of no doubt ; but how many thousand 

 years must it take to make men edentulous when there are 

 so few evidences of a tendency in that direction. The 

 wisdom teeth are said to be disappearing because they are 

 so often ill-developed and frequently never erupted, and 

 the same remark may sometimes be applied to the upper 

 lateral incisors ; -but many Egyptian mummies and Etrus- 



