568 



SCIENCE. 



[N. S. Vol. XXII. No. 



frontal convolution. A paper by Dr. John 

 Punton follows, treating of mysophobia, with 

 a report of a case, and emphasizing the close 

 relation which exists between the so-called 

 neurasthenias and insanity. Dr. Theodore 

 A. Hoch's paper on acute anterior polio- 

 myelitis, begun in the previous number, is 

 concluded, with an exhaustive bibliography, 

 and Dr. William W. Graves contributes a 

 short paper on anesthesia associated with 

 hyperalgesia sharply confined to the areola- 

 nipple area of both breasts, which his experi- 

 ence leads him to consider as a pathognomic 

 and practically constant stigma in hysteria. 



We learn from the British Medical Journal 

 that the publication of a quarterly periodical, 

 to be called the Journal of Tropical Veterinary 

 Science, has been undertaken by Messrs. H. T. 

 Pease, principal of Lahore Veterinary College ; 

 F. S. H. Baldry, professor of sanitary science, 

 Punjab Veterinary College, and R. E. Mont- 

 gomery, assistant imperial bacteriologist. Im- 

 perial Bacteriological Laboratory, Muktesar, 

 TJ. P. Each number will, as far as possible, 

 consist of original articles of scientific inter- 

 est, with reviews and extracts from current 

 literature. Nothing of a personal or political 

 nature will appear in the journal. Amongst 

 the subjects to^ be dealt with in the forth- 

 coming niimbers, for which arrangements have 

 already been made, will be a series of articles 

 on the anatomy, physiology, and pathological 

 conditions of the camel and the elephant; the 

 intestinal and other parasites of animals ; the 

 biting flies and the ticks of India, together 

 with their importance in the transmission of 

 disease. The first number will appear on. 

 Janiiary 1, 1906. The publishers are Messrs. 

 Thacker, Spink and Co., Calcutta. 



DISCUSSION AND CORRESPONDENCE. 

 CYANIDE OF POTASSIUM. 



To THE Editor of Science: Recently when 

 at Minas Prietas, Sonora, at the cyanide plant 

 of Charles Butters, Limited, I observed in one 

 of the settling tanks which was nearly full 

 of pulverized ore, known metallurgically as 

 ' slime,' that the surface of this material, 

 which was saturated with and covered by a 



solution of cyanide of potassium, was pitted 

 by holes and marked by trails, which I as- 

 sumed to belong to some small invertebrate. 

 That they were of organic origin seemed too 

 obvious to be worthy of question. 



There was no opportunity for me to wait 

 until the solution was drawn down sufiiciently 

 to permit of a careful examination of the 

 surface of the pulverized material, so it re- 

 mains for some future observer to determine 

 the identity of the form which produced the 

 markings. 



The observation is communicated to you in 

 the hope that it may invoke a communication 

 of similar observations on the part of others. 

 What seemed remarkable to the writer was 

 that any form of animal life could exist in a 

 solution of cyanide of potassium. 



E. J. H. Merrill. 



SPECIAL ARTICLES. 



the parachute effect of thistle-down. 



The importance of the down of the Canada 

 thistle (Carduus arvensis) for seed distribu- 

 tion is a matter of common knowledge, but it 

 may not be quite so well known just how this 

 is accomplished from a mechanical point of 

 view. 



When the head of the Canada thistle is 

 mature and the day dry (moisture closes up 

 the head even though mature), the scales of 

 the involucre spread and expose the fluffy 

 mass to the air. At this time the achenes 

 may be detached from the receptacle by the 

 slightest force, permitting them to float away 

 attached to the down. This closing of the 

 head is brought about by the unequal turges- 

 cence of the cells in the bracts of the involucre. 



■ The down which grows on the receptacle — 

 not on the achenes — serves the function of 

 helping to keep water from entering the head, 

 thus permitting the achenes to become thor- 

 oughly dry, though the weather may be damp 

 at the time. Dampness tends to hold the 

 achenes fast to the receptacle, and this tends, 

 in some measure, to defeat the purpose of the 

 down, because it may become detached from 

 the achene and float away without its precious 

 burden. Both the calyx-down and the recep- 



