Apeil 31, 1916] 



SCIENCE 



581 



the reaction which follows nervous excitement. 

 This fact, however, merely indicates that there 

 are other mechanisms capable of bringing 

 about the reaction. By stimulating the adrenal 

 glands electrically the melanophores of the 

 entire skin may be contracted. If one leg is 

 ligatured during this procedure, it will remain 

 much darker than its mate; if the ligature be 

 removed several minutes after stimulation has 

 been discontinued, the leg will quickly become 

 as pale as the rest of the body. If the gland 

 be isolated from the general circulation by a 

 ligature, no contraction of the melanophores 

 will follow the stimulation of its surface. 



From the foregoing it is clear that the 

 melanophores of the horned toad are coordi- 

 nated, in part, through the action of a hormone. 

 There is some circumstantial evidence that 

 this hormone is adrenin. Experiments are in 

 progress designed to give more direct evidence 

 concerning the latter point. 



Alfred 0. Eedfield 



Eeferences 



Cannon, W. B., and de la Paz, D. 1911. Emo- 

 tional Stimulation of Adrenal Secretion. Am. 

 Jour. Physiol, Vol. 28, pp. 64-70. 



Elliott, T. E. 1905. The Action of Adrenalin. 

 Jour, of Physiol, Vol. 32, pp. 401-467. 



FuCHS, B. P. 1914. Der Parbenwechsel und die 

 chromatisehe Hautfunktion der Tiere. Hand- 

 hueb der vergleich. Physiol, herausgegeben von 

 Hans Winterstein. Bd. 3, Halfte 1, Teil 2, pp. 

 1,189-1,656. 



Laurens, H. 1916. The Enactions of the Mela- 

 nophores of Amblystoma larva — the Supposed 

 Influence of the Pineal Organ. Jour. Exp. Zool, 

 Vol. 20, pp. 237-261. 



LlEBEN, S. 1906. XJeber die Wirkung von Ex- 

 trakten chromafSnen Gewebes (Adrenalin) auf 

 die Pigmentzellen. Centralbl f. Physiol, Bd. 

 20, pp. 108-117. 



Spaeth, E. A. 1916. Evidence Proving the Mela- 

 nophore to be a Disguised Type of Smooth 

 Muscle Cell. Jour. Exp. Zool, Vol. 20, pp. 193- 

 215. 



SOCIETIES AND ACADEMIES 



THE AMERICAN PHILOSOPHICAL SOCIETY 

 On March 3, Dr. Caroline Eumbold, University 

 of Pennsylvania, spoke before the American Philo- 



sophical Society of Philadelphia on the "Patho- 

 logical Anatomy of Injected Chestnut Trees." 



While working on tree injection in connection 

 with the chestnut-tree blight, about 50 different 

 substances : hydrocarbons, alkali metals and metals 

 were injected in solutions of varying dilution into 

 the trunks of chestnut trees. So far, an examina- 

 tion of the trunks and branches of the trees shows 

 that the reaction of the tree to the injections was 

 alike in kind though not in intensity. This reac- 

 tion varied with the distance from the point of in- 

 jection. The affected region extended up and 

 down the trunk from the point of injection in a 

 line, whose width usually was but little more than 

 the injection hole. As the distance from this point 

 increased the tissues appeared more normal and 

 the area of disturbance decreased. Occasionally 

 all stages of reaction to an injection could be seen 

 in a tree: death — at the point of injection — re- 

 tarded growth, stimulated growth and no reaction. 



The regions that showed response were the cam- 

 bium and the phtem. The cambium as such ceases 

 growth and is wholly converted into wood-tissue. 

 iSmall isolated groups of xylem cells develop on the 

 outside of the rows of normal bast-fiber, through 

 proliferation of the already formed phlcem cells. 

 Large and very numerous stone-cells appear in the 

 phlffim, which increase in number until rows of 

 them are formed. An increased number of cal- 

 cium oxylate crystals form. The isolated groups 

 of xylem, developed in above-mentioned manner in 

 the phlosm, grow in area and coalesce. In this eon- 

 version the cells of the phlcem take part with the 

 exception of the bast-fibers and the stone-cells. 

 They are frequently found embedded in xylem. 

 This conversion proceeds irregularly, leaving areas 

 of phloem surrounded by xylem, or groups of cells 

 of an undecided appearance, apparently partly 

 phlcem, partly xylem. No specimens have been 

 found in which all the phlcem cells in the injected 

 region of the bark had been entirely converted into 

 xylem. 



The conversion of the cells of the phloem into 

 xylem cells is not unknown, but it is believed that 

 this is the first instance in which by injected chem- 

 icals this phenomenon has been produced and it 

 may prove a help in the future histological study 

 of the cells of the phlcem. 



THE BIOLOGICAL SOCIETY OF WASHINGTON 



The 552 d regular meeting of the society was held 

 in the Assembly Hall of the Cosmos Club, Satur- 

 day, March 11, 1916, called to order by President 

 Hay at 8 p.m., with 28 persons present. 



