8o NATURAL SCIENCE. July. 1893. 



the United States of Columbia, British Columbia, British Guiana, South Africa, and 

 New Caledonia has followed pari passu with the introduction and extension of 

 vaccination, which in nearly all these places, without previous inquiry or demand 

 from the inhabitants, has been made compulsory. 



(9.) That as leprosy is a disease of slow incubation, often taking years to 

 declare itself, and in its incipient stages can be detected only by practitioners of 

 large experience, it follows that, in countries where leprosy exists, there is great 

 danger of extending the disease by arm-to-arm vaccination. 



(10.) Leprosy being one of the most loathsome diseases to which the human 

 race is subject, and being practically incurable, it behoves all interested in the public 

 well-being to do their best to prevent its diffusion, and as a means thereto, to dis- 

 courage the practice of vaccination on that ground, if on no other. 



Devonshire Club, St. James's, S.W. William Tebb. 



24th May, 1893. 



Mr. Hick and Calamostachys Binneyana, Schimp. 

 In the letter which appears in the last issue of Natural Science (vol. ii., 

 p. 480), Professor Williamson announces that the "true answer" to my article on 

 "The Fruit-Spike of Calamites " (Natural Science, vol. ii., pp. 354-359) will be 

 given in a memoir which he and Dr. Scott hope to present to the Royal Society 

 before the close of the present year. May I, on my part, refer those who are in- 

 terested in the matter to the forthcoming volume of the Proceedings of the Yorkshire 

 Geological and Polytechnic Society ? There, a paper will be found in which I have 

 given a full description of the beautifully-preserved specimens on which the article 

 is based, so far as it deals with Calamostachys Binneyana, Schimp., as the fruit of some 

 form of Calamites. 



Thomas Hick. 



TO CORRESPONDENTS. 



All communications for the Editor to be addressed to the Editorial 

 Offices, now removed to 5 John Street, Bedford Row, London, 

 W.C. 



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 Haddon & Co., Bonverie House, Salisbury Square, Fleet Street, London, E.C. 



ANSWERS TO CORRESPONDENTS. 



Henry Johnson. — Laurence Oken's library was sold by auction on 17 May, 1853, 

 at Ziirich. It consisted of 5,881 items, 600 of which were Historical, Classical, 

 and Theological books, the rest dealing with the Natural Sciences. 



C. W. K. (Leeds). — You will find that Hagen's Bihliotheca Entomologica (Leipzig, 

 1862) gives the majority of writings on Insects previous to the date of its publi- 

 cation. There is a good index, and you can find out the papers on the special 

 group you want. After Hagen, the volumes of the Zoological Record should be 

 consulted. 



