April 19, 1889.] 



SCIENCE. 



297 



method known to science. The surgeon-general of the Marine 

 Hospital service (who was present) was requested and promised to 

 erect at Tampa, Fla., a similar plant. The administration of ma- 

 rine quarantine, as now carried out by the surgeon-general, was 

 especially commended, and the request was made that more sta- 

 tions and more men be devoted by him to this work. The co- 

 operation of the management of the Plant Line of steamers, plying 

 between Havana and Tampa, with Dr. Burgess, United States 

 medical inspector at Havana, was commended as an example for 

 cleanliness of ships, scrutiny of passengers, and disinfection of 

 baggage. By special resolution, the attention of the secretary of 

 the treasury of the United States was called to the prevalence 

 of smuggling between Cuba and the Florida coast, and the great 

 danger of introduction of yellow-fever by this illicit traffic ; and he 

 was requested to use additional precautions, and, if possible, put a 

 stop to it. On the question of inland quarantine it was decided, 

 that, as far as possible, this should always be declared, where they 

 exist, by State boards of health ; and that by whomsoever declared, 

 within thirty-six hours after the proclamation, comfortable quarters, 

 with provisions and bedding, must be provided for the unfortu- 

 nates detained at the station. The conference, by a decided vote, 

 refused to indorse the proposition that it was necessary to disinfect 

 a town or city in which yellow-fever had prevailed, but in which 

 there had been no cases for several months, and the place had 

 been subjected to the frosts and freezes of winter ; deeming that 

 the use of disinfectants under these circumstances was not only 

 useless, but tended to breed unnecessary terror and distrust not 

 only among the people of the place, but of surrounding States. 



Treatment of Obesity. — Dr. W. T. Smith cgmmunicates to 

 the British Medical J oicrnal a method for the treatment of obesity 

 which he has successfully employed in forty-three cases, including 

 himself. The plan which he follows is to confine the diet to rump- 

 steak, cod-fish, and hot water for fourteen days, with the absolute 

 exclusion of every thing else. Taking meat in large quantities may 

 lead to dyspepsia, but this can be easily overcome by reducing the 

 meat to an essence. This may be done as follows : Take four 

 pounds of beef free from skin and fat ; cut it to pieces about an 

 inch square ; place the meat in a close-fitting, air-tight jar ; stand 

 the jar in a pan of boiling water, and let it simmer for six hours. 

 Pass the juice of the meat thus obtained through a sieve ; then 

 measure four ounces of the fibrine of the meat ; pulverize it in a 

 mortar, and stir it up with the essence ; divide this into four doses, 

 and you will obtain the nitrogenous elements required of the quan- 

 tity of meat to be taken at one meal. There is also a similar way 

 of obtaining meat-essence by using a pot called "Boule Ameri- 

 caine." In treating his cases, in several instances he has been 

 obliged to modify the amount of hot water, and lessen occasionally 

 the quantity of meat ; but as regards his own personal experience, 

 he found that three pounds of rump-steak and one pound of cod- 

 fish were hardly sufficient to satisfy his appetite. The meat diet 

 and hot water alone must be regularly adhered to for fourteen 

 days ; and the amount of hot water taken at any time during the 

 day, commencing at seven in the morning and finishing at half- 

 past ten at night, varies from six and one-third pints, more or less, 

 according to the powers of the patient. The second epoch of 

 twenty-one days the diet may be considerably varied, as he reduces 

 the hot water to four pints in the twenty-four hours ; and he allows 

 other kinds of meat, such as mutton-chops free from fat, and 

 chicken ; and, as regards fish, grilled turbot, whiting, or soles ; a 

 little green vegetable, and some slices of plain unsweetened rusk. 

 The third epoch, thirty-one days, the hot water is reduced to about 

 a quart a day, and he allows tea, stale bottom crust of household 

 loaf, captain's biscuits, grilled fish, fowl, game, turkey, any joint, 

 hock or claret, with seltzer-water, in place of whiskey. As hot 

 water is very unpalatable, a slice of lemon may be added to each 

 tumbler. No case of obesity should be treated by this method 

 when the patient is suffering from any organic disease, unless it be 

 some trifling malady. The loss of weight in nearly all cases will 

 vary somewhat ; but Dr. Smith states that his patients bear the 

 treatment exceedingly well, and express themselves as feeling far 

 better in health, and able to take exercise with comfort. The first 

 period of fourteen days is really the only hardship, and he has 

 found very little difficulty in persuading patients to stick to the 



diet. As some alkali is essential, he prescribes five grains of the 

 bicarbonate of potassium, to be taken night and morning. Dr. 

 Smith offers to send his diet-cards to any medical practitioner who 

 will write to him, but asking that the result of any case put under 

 treatment be reported to him. 



ELECTRICAL NEWS. 



The Clark Cell as a Source of Standard Currents. 



For measuring small currents, there are two methods which 

 should give good results. The first is by the use of an electro- 

 dynamometer, where the mutual actions of circuits carrying the 

 current are balanced by known weights. In this instrument the 

 changes in the magnetic field do not affect the results ; and but for 

 its inconvenience, and the fact that continuous readings are im- 

 possible, electro-dynamometers would be universally used. In the 

 second method an ordinary galvanometer of any convenient pat- 

 tern could be employed, provided it could be easily calibrated in 

 order to eliminate errors due to changes in the earth's field or to 

 the field due to magnets on the instrument itself. In order to 

 effect this calibration, Messrs. Threlfall and Pollock have en- 

 deavored to obtain a galvanic cell whose electro-motive force will 

 remain constant ; and, by sending a current from this through a 

 known resistance, the value of the current is known, and it can be 

 used to standardize a galvanometer meter. In the form of instru- 

 ment chosen, a movable coil was employed, with an adjustable 

 directing magnet. To calibrate it, the coil was moved to a marked 

 position, a current from the standard cell was sent through it, and 

 the directing magnet moved up or down until the deflection reached 

 a certain set value. This can be easily and rapidly done. 



The standard cell was of the Clark type, now almost universally 

 used for comparisons of electro-motive force. From the ordinary 

 type, only an extremely small current can be taken, or the electro- 

 motive force will drop and the cell be ruined. In the type devised 

 by Messrs. Threlfall and Pollock, a much larger surface than or- 

 dinarily used was employed. In a paper read before the London 

 Physical Society the gentlemen named give the result of a long 

 series of experiments on these cells. The conclusions at which 

 they arrive are as follows : — 



I. When a current is taken from a Clark cell, the terminal electro- 

 motive force drops practically instantaneously to within an inap- 

 preciable amount of its final value. 2. To the first degree of ap- 

 proximation, this value is constant. 3. There is no appreciable 

 secular change. 4. When the current is stopped, the terminal 

 electro-motive force rises instantly to within a few thousandths of a 

 volt of the original value. 5. The cell completely recovers in time. 

 6. The above statements are only true when the current does not 

 exceed a certain value, depending on the size of the cell. For a 

 cell in which the zinc and mercury surfaces have each a value of 

 five inches or upward, .001 of an ampere will not be too great; for 

 the ordinary cell used as a standard of electro-motive force, the 

 current should not exceed one hundredth of this value. 7. When 

 too large a current is taken from any cell, the electro-motive force 

 goes on dropping for some time, after which it rises slightly, and 

 seems to tend toward a fixed value. 



The Detroit Secondary Battery. — One of the new sec- 

 ondary batteries which has been attracting considerable attention 

 during the past few months is the Detroit battery, manufactured 

 by the Woodward Electric Company of Detroit, Mich. It is of the 

 Faure type, with a support-plate of lead and active material con- 

 sisting of salts of lead in cavities in the support. The method of 

 making the support-plate is decidedly novel. Rock salt is put into 

 a square mould, and is baked. Melted lead is then run into the 

 mould and allowed to solidify. The cube thus formed is sawed 

 into plates, and the salt is dissolved out of them by putting in warm 

 water. The result is a plate full of cavities of irregular shapes, 

 having in general an overlapping portion, which prevents the active 

 material from falling out. A solid rim with a lug for a terminal is 

 cast around this central porous portion, and then red lead or litharge 

 is pasted into the cavities. The plates are then put in a cell con- 

 taining sulphuric acid, and formed by sending a current of electricity 

 from the positive to the negative set. The Detroit batteries have 



