148 



POPULAR SCIENCE NEWS. 



[October, 1888. 



being submitted to entire destruction. At present 

 the general regulations are the following: A 

 tuberculous animal is put apart, and cannot be 

 displaced unless for the purpose of having it killed. 

 Its flesh can be sold for alimentary uses so long as 

 the tuberculosis has been recognized to be local ; 

 that is, to be confined to visceral organs and to 

 the corresponding ganglia. The hides are not 

 allowed to be used unless they have first been sub- 

 mitted to disinfection. The milk of tuberculous 

 cows can be used only for animals, after boiling. 

 These regulations are wise, being sufficiently strict 

 for the protection of public health, and keeping 

 quite abreast of the present state of science. M. 

 Nocard communicated some experiments of an 

 important nature, showing that the juice of the 

 meat of tuberculous oxen does not contain any 

 bacilli, and is utterly harmless. It is known, how- 

 ever, that under certain circumstances the blood 

 may contain a number of bacilli. These bacilli 

 are, of course, transported in the whole body, and 

 a large part comes in the muscular tissues. Here, 

 however, they do not remain long; and before a 

 week has elapsed they have been entirely destroyed 

 in and bi/ the muscular tissues by which they are 

 digested, so to speak. So, upon the whole, the 

 meat of tuberculous animals is to be considered as 

 vei-y faintly or not at all dangerous to public 

 health, and under proper restrictions its sale is to 

 be allowed. jNIilk when the mammary glands are 

 not tuberculous is not dangerous; but, as one can- 

 not ascertain the exact origin of the milk sold in 

 cities, it should always be boiled, as experiments 

 have shown that the boiling kills all the bacilli. 

 Impure milk makes impure cream and butter, as 

 M. Bang of Copenhagen has seen, and great care 

 must be taken as to the origin of these. 



M. Arloing gave some Information concerning 

 experiments he is making. He is trying to find a 

 bacillus that is able to kill that of tuberculosis, or 

 a disease that could be inoculated without great 

 inconvenience, and would preserve against tuber- 

 culous inoculation. He has tried typhoid bacilli 

 without any success : they seem to render the 

 progress of tuberculosis easier and more rapid. 

 However, he believes something may be found that 

 will prove useful. 



The Revue Scientifique has published, under ]M. 

 de Lapparent's name, a good paper on the proposed 

 submarine tunnel between England and France. 

 He is a strong advocate of the enterprise, on com- 

 mercial grounds, and pronounces the work of an 

 easy realization. The scheme o£ a bridge he does 

 not relish at all, and thinks the structure would 

 not last long. It is, however, a queer thing to see 

 how the English affect to believe that the tunnel 

 would be a great danger to them, while the notion 

 has never come to the French that it would be one 

 to themselves. No one will believe that there is 

 any difficulty at all in protecting the entrance of, 

 such a tunnel, and in preventing an army from 

 coming through it from the opposite side. 



Interesting experiments have been recently 

 made in Russia, and published in France, on the 

 culture of vegetal parasites for the destruction of 

 injurious insects. The result is, that, in works 

 specially gotten up for the purpose, spores of Isaria 

 destructor have been abundantly and easily culti- 

 vated at small cost, and have proved exceedingly 

 useful for the destruction of Cleonus punctiventris 

 and other Coleoptera, which are very injurious to 

 beet-root. Other vegetal parasites are known that 

 are destined, perhaps, to become some day of great 

 use, such as Entomophtlwra grylli, which kills the 

 genus Gryllus ; others which have destroyed large 

 quantities of Panolis jiiniperda, etc. In his paper, 



published in the Memoires des Naluralistes de la 

 Noiivelle Rusaie, M. Krassilstchik gives an enumera- 

 tion of such parasites, and of the epidemics they 

 have brought on insects, so far as be knows. It 

 may be hoped that many insects that are extremely 

 injurious to fruits or crops could be destroyed by 

 the use of some of these parasites, and be prevented 

 from doing such mischief as they do. If some 

 vegetable could be found that could destroy the 

 Algerian locusts, it would be a public good for 

 France's large colony, which has been this year 

 again visited by the terrible plague. 



Two French engineers have projected to build 

 for the Exhibition a large terrestrial globe of forty 

 metres circumference ; that is, at the scale of one- 

 millionth. This globe is to be supported on a 

 strong column, on which it will rotate, describing 

 a whole turn in twenty-four hours; and circular 

 galleries around it will allow of an easy inspection. 

 The idea is a very good one, and if properly car- 

 ried out, — and generally Frenchmen do under- 

 stand the execution of such plans, — will be a real 

 attraction for all. 



M. A. d'Assikr, examining the questionem vexa- 

 tam of the earth's age, arrives at the conclusion that 

 it is about half a million of years for the nebular 

 and stellar period, and about twenty-five millions 

 (of which fifteen are passed) for the period of 

 organic beings. When about twenty-six million 

 years old, our mother-earth, cold and lifeless on 

 account of the sun's disappearance, shall be some- 

 what shaken in consequence of the moon rushing 

 on her, and some time later will in turn rush in 

 the sun. This affectionate meeting, if M. d'Assier 

 is well informed, will cause a momentary outbreak 

 of heat and light, and thus the earth will have 

 done with its troubles. 



M. Pasteur read at the last meeting a paper 

 which has been creating a good deal of sensation. 

 This paper is from Dr. Gamaleia, director of the 

 anti-rabic laboratory of Odessa. M. GamaTe'ia 

 claims to have discovered the method of preventing 

 cholera by preventive vaccination. Ordinary cul- 

 tures of the cholera bacillus are endowed with a 

 very feeble virulency, and M. (iamalela says that 

 the first step in the preparation of the vaccination 

 matter consists in increasing this virulency. This 

 is easily obtained by cultivating it in a pigeon 

 after it has passed through a guinea-pig. This 

 strong virus is cultivated in broth, and then sub- 

 mitted to the temperature of 120° Centigrade dur- 

 ing twenty minutes, to kill the bacilli. This ster- 

 ilized culture is very virulent yet, as it contains a 

 substance which kills rapidly the animals which 

 are inoculated with it, although it contains no 

 more bacilli. If this sterilized culture is inoculated 

 in small quantities at different times (twelve cubic 

 centimeters of the broth in two or three doses in 

 as many days, for instance, for the pigeoti), it does 

 not kill, but acts as a preventive; and the most 

 virulent culture may be inoculated without causing 

 any choleraic symptoms. M. Gamaleia claims that 

 his " chemical vaccine " — it is a chemical, with- 

 out living organisms — confers a complete immu- 

 nity against cholera. He proposes to come to 

 Paris to repeat all his experiments in Pasteur's 

 laboratory, under the eyes of a special committee 

 of the Academy of Sciences, and to find, by ex- 

 periments on his own person, the dose that is 

 necessary for anti-choleraic vaccination. This pro- 

 posal has been accepted, and the Russian scientist is 

 to come in November to repeat all his experiments. 

 The readers of the Popular Science News will be 

 kept au courant of this very important discovery. 



H. 

 Paris, Aug. 22, 1888. 



SCIENTIFIC liKEVITIES. 



Speed of Electricity. — There is, as Pro- 

 fessor Thompson remarks, no assignable " velocity 

 of electricity," as this must vary with the current 

 and the conductor. Wheatstone, in 1833, seemed 

 to show a transmission velocity of 183,000 miles a 

 second through copper wire ; but in late experiments 

 signals were sent over ordinary telegraph vrires on 

 poles, and hadarate of only 14,000 to 16,000 miles. 

 With wires near the earth, the velocity was 12,000 

 miles, but reached 24,000 on very high wires. 



Application of the Electrolysis of Cop- 

 per TO THE Measurement of Electric Cur- 

 rents. — In the process of standardizing Sir 

 William Thomson's new electrical instruments, 

 Mr. Gray has been led to examine the accuracy 

 of the method by means of jthe deposition of 

 copper, and concludes that the constant of an 

 electric-current instrument can be obtained with 

 certainty, by this method, to one-twentieth of one 

 per cent. 



Why do they? — A correspondent of an ex- 

 change writes, " Apropos of left-handedness, I 

 should like to see a satisfactory explanation of the 

 fact that women always (with exceedingly rare 

 exceptions) button from right to left, and men 

 from left to right. Personally I have remarked 

 only four cases of exception to the rule." 



Influence of Light upon Electrical Dis- 

 charges. — Hertz, in a previous number of the 

 Annalen der Physik, having called attention to a 

 remarkable influence of the ultra-violet rays upon 

 electrical discharges, E. Wiedemann and II. Ebert 

 repeated his researches, and have confirmed his re- 

 sults. When a spark will no longer pass between 

 the terminals of a Ruhmkorff coil, if a beam of 

 ultra-violet light falls upon the electrodes, the 

 spark will traverse the interval between the elec- 

 trodes. Wiedemann and Ebert show that the effect 

 is also produced by the light of burning magne- 

 sium, and that the effect is confined to the ultra- 

 violet rays, red and green producing no effect. 

 The effect is produced at the negative electrode, 

 and not at the positive. 



In testing Chemically Certain Filaments 

 said to be of a material other than carbon, Mr. 

 Desmond Fitz-Gerald boiled them in strong sul- 

 phuric acid, with tlie view, if carbon were present, 

 of obtaining carbonic oxide and sulphurous acid 

 according to the reaction 



II.SO, + C = CO + HjSOa. 

 No such reaction occurred, the filaments in ques- 

 tion remaining unaltered. Before committing him- 

 self, however, to the conclusion that no carbon was 

 present, the experimenter took the precaution of 

 repeating the experiment with filaments known to 

 be of carbon. These filaments also remained un- 

 altered after prolonged boiling in the acid. This 

 result justifies the conclusion that the carbon of 

 lamp filaments, unlike ordinary carbon, is not 

 acted upon by sulphuric acid at its boiling-point. 



The Duration of Lightning Flashes is ob- 

 tained by observing the heating effect produced upon 

 some substance through which we know the whole of 

 the flash has passed, and comparing that effect with 

 the effects produced in a laboratory by the passage 

 through the same kind of substance of a known 

 current of electrioity for a known time; then, by 

 observations upon the duration of lightning flashes, 

 we can calculate the quantity that must have 

 passed in order to produce the observed effect. 

 Thus, it is reported that in 1772 lightning struck a 

 bar of iron on the top of the dome of St. Paul's and 

 made it red-hot. The bar W3« four inches broad 

 and one-half inch thick. Wheatstone estimated, 

 by means of his revolving mirror, that the duration 

 of a flash certainly does not exceed the millionth 

 part of a second. 



