SCIENTIFIC.

Otago Witness, Issue 1700, 21 June 1884, Page 28

SCIENTIFIC.

— We have had much sympathy for the fly, says Good Health, believing tbe little creature to be a pretty good sanitarian on account of the avidity with which it devours germs, as it consumes prodigious numbers of thorn ; but if what Dc Grassi says of those little creatures is true, we must cease to defend them, and begin a war of extermination. We present the following facts at the present time, so as to give an opportunity to prepare for protection against these newly discovered enemies of life and health : It_ was always recognised that these insects might carry the germs of infection on their wings or feet, but it was not known that they are capable of taking in at the mouth such objects aa the ova of various worms, and of discharging them again unchanged in their fasces. This point has now been established, and several striking experiments illustrate it. >Dr Graasi ex posed in his laboratory a plate containing a great number of the eggs of a human parasite, the tricocephalus dispar. Some sheets of white paper were placed in the kitchen, which stands about 10 metres from tho laboratory. After some hours the usual little spots produced by the fsecea of flies wera found on the paper. These spots, when examined by the microscope, wore found to contain some of the eggs of tbe tricocephalus. Some of the flies themselves were then caught, an<i thoir internes presented large numbors »f the ova. Similar experiments with the ova of the oxyuris vermicularis and of the tcenia solium, aiforded corresponding results. Soon after the flies had some mouldy cream, the odium lactis was found in their fseces. Dr Grassi mentions au innocuous, and yet conclusive, experiment that everyone can try. Sprinkle a little lycopodium on sweetened water, and afterwards examino the froces and intestines of the flies ; numerous spores will be found. A.s flies are by no means particular in choosing either a place to feed or a place to defecate, often selecting maat or food for the purpose, a somewhat alarming vision of possible consequences is raised. Dr Grassi invites the attention of naturalists to the subject, and hopes that some effectual means of destroying flies may bo discovered.

—There seems, at last, to be a definite plan and determination to at least partially utilise Niagara Falls. Reports from Inckport, New York, of March 18th, says : Colonel Leonard Henkle, the inventor of a system of electric lighting which he proposes to transmit to 65 cities in the United States, from central batteries^ stationed at Niagara Fulls, and run by the immense water power there, was interviewed in this city to-day by reporters. On Sunday he received a Jotfcor from a Chicago banker, who has taken 51,000,000 of the stock, abating that he was soon coming east to Baltimore, which city he would make hi« headquarters. He will there take charge of the company and form t a syndicate in New York City to go on with the work. Colonel Henkle is now having a cottage built at Niagara Falk, which will be ready for his occupancy in May, and he will then go thero ro superintend the work of ejecting buildings for the batteries and digging a canal to obtain the water power. The power will bo transmitted in a silver wire about the size of a straw, laid underground, inclosed in heavy pipes made of asphalfcum. Such a -wire, the Colonel states, can, with a forty -foot battery at the Niagara Falls end, transmit in four hours to Rochester enough electricity to light that city for twelve hours. The sixty-five cities are all over 30,000 popula tion. Lockport and Buffalo will probably bo the first places where he will introduce his apparatus .is experimental points, and he expects that he will be able to make those experiments next fall. By a properly-constructed means for conservation of electric energy, he expects to overcome the resistance usually found in transmitting currents through long distances.

—The Frankfurter Zeifcung informs us that Dr Reinsch has found, as the result of a long series of minute investigations, that the surface of 50 pfennig pieces (sixpences) which havo been long in circulation are the home and feeding ground of a minute kind of bacteria and vegetable fungus. An extended series of .observations showed that this is the case, with the small coins of all nations, the thin incrustation of organic matter deposited'upon their surfaces in the course of long circulation rendering thorn very suitable for this parasitical settlement. Dr Reinsch scraped off some of these incrustations and with a small scalpel divided them into fragments, which were subsequently dissolved in distilled water. The employment of lensea of very high power showed the bacteria and fungi distinctly. This is a matter of no little importance from a hygienic point of view. It has now been conclusively established that bacteria form the chief agency in the propagation of epidemic disease. The revelation that they have chosen domicile in the most widely circulating medium which probably exists in the world presents us with a new factor in the spread of infectious disease. There is, however, a remedy. Where coins have been in circulation for a number of years, if they are washed in a. boiling weak solution of caustic potash they will be cleansed from their organic incrustation, and so freed from the unwelcome guests which they harboured.

—A small electric engine has lately been on exhibition in New York, having a piston movement, and claimed by the inventor to be the first of that kind which has been manufactured in this country. The engine is supplied from a battery and consists of four electromagnets, two on each side, with armatures of permanent magnets. While one attraots, another repels, giving the piston-movement of the common steam locomotive, and the little engine ia similar to this in the remainder of its mechanism. This engine of two horse power, the inventor says, will revolve from 600 to 1000 times per minute. It costs 150dol, and the electricity of a storage battery to run it a day of 12 hours will cost, he estimates, 50 cents. It takes up little space, and can easily be placed under a car. Its inventor also hopes to adapt it to road carriages, and believes that cabs can bo run by it for 50 cents a day.