520 



SCIENCE 



[N. S. Vol. XL. No. 1032 



cyanide and plugged it up. In two days the 

 scale began to fall from the tree and in a few 

 days all appeared dead. Others hatched and 

 attacked the tree, but lasted only a short time, 

 and the tree has since been free from scale and 

 very vigorous. 



At the same time I bored a similar hole in 

 an old peach tree which seemed to have passed 

 its usefulness and put a like charge of potassie 

 cyanide in it. The tree has since seemed more 

 vigorous than before, and raised a fair crop 

 of peaches. After feeding some of them to 

 chickens and a rabbit with no apparent ill 

 result, I ate some of the peaches, and could 

 find nothing wrong with them. I have since 

 put a similar charge of the cyanide in an 

 orange tree with no apparent bad effect. 



It would seem from this experiment that it 

 is possible in some kinds of trees, at least, to 

 poison scale and sap-eating insects without 

 injury to the tree. The method would seem 

 to be especially adapted to killing various 

 kinds of borers and insects which, like the 

 pine beetles, burrow beneath the bark. 



Fernando Sanford 

 Stanford University, Cal., 

 September 3, 1914 



laboratory cultures op amoeba 

 To THE Editor of Science: While Amoeba 

 may appear in hay infusions within five days, 

 even when in sufficient quantity, it is often not 

 desirable for laboratory study on account of 

 its extremely small size. Again standard text- 

 books of general biology give tolerably certain 

 methods for obtaining the organism, within, 

 however, a much longer time — in some cases 

 from 5 to 6 weeks. The writer hopes that 

 certain notes on this part of the laboratory 

 routine may be of help. 



In preparing laboratory cultures of Ammha 

 during the past three years, he has been led 

 to collect material for his infusions from a 

 number of different types of environment — 

 stagnant and freshwater ponds, swamps, sew- 

 age polluted streams, etc., and to make com- 

 posite cultures of the material obtained. Such 

 cultures, if not infertile, in the writer's ex- 

 perience rapidly attain the peculiar balance 



necessary for the flourishing growth of the 

 organism, and yield in a comparatively short 

 time, in one case as early as six days, a type of 

 Ammia, which, if not always large, presents 

 considerable advantage over that inhabiting 

 the hay infusion. Such cultures have been 

 available for study as long as eight days. Very 

 frequently, too, there are produced an abun- 

 dance of Spirillse, etc., which the Amcehce 

 obligingly ingest, while the whole microcosm 

 seems to be one superior to that obtained in 

 the infusion as ordinarily made. A number 

 of control cultures made at the University of 

 Pittsburgh and the Osborn Zoological Labora- 

 tory, Tale University, showed that Amoeba 

 eventually appeared in one or more of the com- 

 ponents of the composite culture, but in every 

 case later. Without any attempt at explana- 

 tion, it seems to the writer, that there may 

 be some parallelism between the condition of 

 environment obtained in such a composite 

 culture and that in the " varied environment 

 medium " as described by Woodruff.'^ In con- 

 clusion, it is noted that the results of the ex- 

 periments have always remained fairly uni- 

 form, although widely separated geographical 

 localities have been involved. 



N. M. Grier 

 Biological Laboratory, 

 University op Pittsburgh 



THE origin of MUTATION 



The word mutation appears to have sud- 

 denly arisen in 1650, according to Lock. It 

 appeared again independently two hundred 

 and nineteen years later. This recent advent 

 (1869) has been termed the " Mutations of 

 Waagen" (1912). Darwin at times spoke of 

 species as " mutable," and de Vries (1901) has 

 made the word famous. 



Since in the pages of this journal and else- 

 where in the States there has been an attempt 

 to show that the word was preoccupied in a 

 sense different from that in which de Vries 

 used it, the following quotation from Lock, 

 " Eecent Progress in the Study of Variation, 

 Heredity and Evolution,"- may be interesting. 



1 Americam, Naturalist, XLII. 



2 Third edition, 1911, p. 124. 



