SCIENTIFIC NEWS. 



[April 27, 1888. 



CORRESPONDENCE. 



The Editor does not hold hitnself responsible for opinions expressed 

 by his correspondents, nor can he take notice of anonymous com- 

 munications. All letters must he accompanied by the name and 

 address of the writer, not necessarily for publication, but as a 

 guarantee of good faith. 



MILK AS A VEHICLE OF DISEASE. 



In your journal of the 23rd ult. is a reference to milk as a 

 vehicle of disease. Permit me to remark that the fact that 

 scarlatina has been conveyed by milk is admitted by all un- 

 prejudiced students of the subject, and that, under certain 

 conditions, tuberculosis may be communicated by the milk 

 of tuberculous animals is no less certain ; but this is quite a 

 diiferent thing from their being piimarily bovine diseases. 

 No one who is competent to form an opinion at all has ever 

 even suggested such a notion. 



Pure cultures of the tubercle bacillus have conclusively 

 proved the bacterial nature, infectiveness, and consequently 

 comraunicability, of the disease, by inoculation, by inhala- 

 tion, and by the consumption of milk containing the bacilli, 

 which it does when, and only when, the mammary glands 

 are implicated, or when, as in so-called acute miliary tuber- 

 culosis, the entire fluids of the body, the blood, and lymph 

 contain the bacilli. 



The identity, too, of the tubercular process and of the 

 pathogenic organisms in man and beast, notwithstanding 

 some differences in the appearances exhibited in, for ex- 

 ample, human tubercular pleurisy and bovine pearl disease, 

 is also established. But that man and cow may be attacked 

 by the same specific disease, does not prove that man gets 

 it from the cow, or the cow from man. As regards tubercu- 

 losis, there is a virtual consensus of opinion among 

 pathologists, but not, as the writer of your article 

 imagines, on the question of scarlatina. This is in- 

 disputably, primarily and essentially, a human disease ; 

 milk may serve as a vehicle just as clothes 

 may ; or, and here lies the problem for solution, scarlatina 

 may be communicated from man to the cow, and then again 

 to man ; or lastly, though it is highly improbable, it may be 

 a disease common to both. To put the matter in the fewest 

 possible words, the hypothesis advanced by Dr. Klein, and 

 which I provisionally accept, is that, under conditions at 

 present not ascertained, the cow is capable of contracting 

 from man the human disease scarlatina ; that in the cow it 

 mostly manifests itself in such cases in a greatly modified 

 form, with little fever or disturbance of health, the local 

 lesions being most conspicuous on the udders, and by some 

 confused with, though essentially different from, those of s o- 

 called cow-pox and other vesicular diseases. 



That this, the Hendon disease, can be communicated to 

 man by direct inoculation, with identical symptoms ; but 

 milk being, as experiment shows, the very best culture fluid 

 for the bacillus, it tends, when the milk of affected cows is 

 kept for a few hours, to resume its pristine character and 

 virulence, and the ingestion of such milk induces in the calf 

 a form of the disease, pathologically less removed from the 

 human scarlatina, and in man the fever, with all its usual 

 character, and capable of reproducing itself from the new 

 foci, so that an epidemic may be set up in a place without 

 the introduction of a human individual already infected. 



Such is the position assumed by the most advanced arnong 

 us as a working hypothesis. Of bovine origin of either 

 tuberculosis or scarlatina, no one in his senses dreams. 



Edward F. Willoughby. 



THE LEMMINGS OF NORWAY. 

 Can any of your correspondents give us some plain truth 

 concerning the ways of these little animals ? What we read 

 about them savours strongly of mythology. Has Mr. 

 Matthieu Williams observed them in their native haunts ? 



Yetholm. 



RECENT INVENTIONS. 



The following list has been compiled especially for the SCIENTIFIC 

 N EWS by Messrs. "VV. P. Thompson and Boult, Patettt Agents, of 

 "1,21, High Holbom, London, W.C. ; Newcastle Chambers, Angel 

 Row, Nottingham ; Ducie Buildings, Bank Street, Manchester; 

 and 6, Lord Street, Liverpool. 



Hearing Trumpet. — Mr. A. Young, Edinburgh, has 

 patented a hearing trumpet. The bell of the trumpet is 

 formed with the lower side slightly concave, the upper side 

 being semi-circular or arch-shaped. The bell passes back' 

 wards and is formed U-shaped ; the tubular part passes 

 downwards and ends in a contracted part in which a tube 

 slides telescopically. A curved nipple, entering the ear, 

 slides and swivels on the end of the tube. The bell is 

 attached by its under surface to an elastic strip which 

 terminates over the temples, thus holding the trumpet in 

 position ; a rear fastening consisting of a spring wire 

 loop is hidden in the hair or otherwise secured. 



Fountain Penholder. — Messrs. S. Harrison and J. 

 Mara, both of Manchester, have patented a fountain pen. 

 This is an ordinary hollow penholder, having holes in its 

 sides, the said holes being covered by a flexible material. 

 Upon pressure being applied to this material the pen is 

 supplied from the interior of the holder with the writing- 

 fluid through a small orifice at the bottom of the holder. 

 The holder is made in two pieces, one fitting into the 

 other, for easy refilling. 



Ventilating Apparatus. — An air propellor has been 

 patented by Messrs. J. Crighton, R. Crighton, and G. C. 

 Peel, of Manchester. This invention relates to the con- 

 struction of revolving air propellors used for ventilating 

 purposes. The vanes ot the propellor are constructed 

 in a hollow curved scoop-like form, and are driven with 

 the concave sides of the vanes forwards, by which means, 

 instead of acting centrifugally, as in an exhaust fan, the 

 vanes scoop the air towards the centre, and drive it 

 forwards rapidly along the central portion of the tube, 

 and thus the friction of the current of air against the 

 inner circumference of the conducting tube is reduced 

 to a minimum. 



ANSWERS TO CORRESPONDENTS. 

 C. N. Welman. — Your communication is of too speculative 

 a nature for our columns. 



Torpedo Apparatus. — An apparatus for feeding and 

 supporting torpedoes to the discharging apparatus has been 

 patented by Messrs. W. C. Storey and G. Poore, Queen 

 Victoria-street, London. According to this invention, 

 torpedoes are carried in suitable supports at the rear of 

 the discharging tube, and are arranged in a circle with 

 their axes in planes parallel to that of the discharging 

 tube. The torpedoes are supplied to the discharge tube 

 by causing the supports that carry them to move so as 

 to bring the torpedoes successively in line with such 

 tube, into which they are then forced by manual or 

 suitable mechanical means. 



Hydrogen Gas. — An apparatus for producing hydrogen 

 gas by a dry method has been patented by Messrs. W. 

 Majert and G. Richter, Germany. This invention is 

 based upon the property which zinc dust possesses, when 

 heated in the presence of certain bodies containing water, 

 of decomposing the latter, so as to form oxide of zinc and 

 hydrogen gas. Cartridges are constructed containing 



