324 



SCIENCE 



[N. S. Vol. XLI. No. 1052 



In the University of London, Dr. Edward 

 Barelay-Smitli, of Cambridge, succeeds Pro- 

 fessor Waterston in the chair of anatomy at 

 King's College, and Dr. E. P. Cathcart, of 

 Glasgow, succeeds Professor Leonard Hill in 

 the chair of physiology at London Hospital 

 Medical College. 



DISCUSSION AND COBSESPONDENCE 



EFFECT OF CYANIDE OF POTASSIUM ON TREES 



To THE Editor of Science: My attention 

 has been attracted to an article in your 

 columns by Professor H. A. Surface relative 

 to the use of cyanide of potassium for elim- 

 inating insect attacks on trees. While I have 

 not investigated the claim of the firm at 

 Allentown, Pennsylvania, referred to in his 

 article, and know nothing about their process, 

 however, from my own results with cyanide 

 of potassium, especially on elms and black 

 locusts, I am convinced it is a valuable 

 remedy. 



The article above referred to gives the gen- 

 eral impression that cyanide of potassium is 

 the cause of tree death as well as various stain- 

 ing eilects found in the bark, cambium, etc. 

 My opinion is that the staining comes from 

 the reaction between the tannic acid found in 

 all trees and the iron found in this so-called 

 " tree food " in the form of iron sulphate. It 

 is well known that when solutions of tannic 

 acid are brought into contact with iron or any 

 iron salt, dark colored compounds resembling 

 ink are formed. These are very permanent 

 dyes and no doubt account for the dark color 

 observed. 



The cyanide of potassium as I have used it 

 for years in eliminating borers from various 

 trees has never caused any staining, nor have 

 I ever known of its killing or in any way in- 

 juring a tree. I have been using it and pre- 

 scribing it for the use of others for about 

 twelve years in connection with my forestry 

 work, and we have saved the lives of thou- 

 sands of trees by means of it. 



Large groves of thrifty elms and black 

 locusts in Kansas and other parts of the west 

 have been completely rescued from the attacks 

 of boring and girdling insects by means of 



cyanide of potassium, and this article is the 

 first intimation I have ever had to the efFect 

 that it is deleterious to tree growth. I am 

 strongly inclined to feel that the blame is not 

 properly placed and that a highly useful 

 chemical for insect eradication is being con- 

 demned because of damages produced by other 

 substances. C. H. Shattuok 



University op Idaho 



gossypol — a toxic substance in cottonseed, 

 a preliminary note 



We have separated from cottonseed kernels 

 a substance which appears to be identical with 

 the substance which Marchlewski'- separated 

 from crude cottonseed oil and called gossypol. 



We have administered in various ways, to 

 rabbits, gossypol as prepared by us and have 

 found it toxic in every case. 



We have found as did Marchlewski that 

 gossypol is quickly oxidized in an alcoholic 

 solution of sodium hydroxide. 



In a previous paper from this station^ it 

 was stated that " (alcoholic) alkaline treat- 

 ment, very greatly diminishes if it does not 

 entirely remove the toxic properties of the 

 (cottonseed) meal," and it was suggested that 

 the beneficial effect " may be due to hydrolysis 

 or to the formation of a sodium salt or to 

 some other change not yet determined de- 

 finitely." 



We now offer as an explanation that gossypol 

 is a toxic substance and that its oxidation by 

 an alcoholic alkali renders it nontoxic and 

 thus diminishes if it does not entirely remove 

 the toxic properties of cottonseed meal. 



W. A. Withers, 

 F. E. Carruth 



N. C. Agricultural 

 Experiment Station, 

 Ealeigh, N. C, 

 December 31, 1914 



SCIENTIFIC BOOKS 

 Bausteine zu einer Biologischen Weltam- 

 sclmuung. Von Jakob, Baron von Uexkull. 

 Miinchen, F. Bruckmann A.-G. 1913. 



ij. fiir PraJct. Chem. (1899), 60, p. 80. 



2 Withers and Eay, Science (1912), 36, p. 31. 



