648 EXPERIMENT STATION RECORD. 



tion, manufacture, insect pests, and diseases. The total ncro.ige planted with 

 rubber at the end of 1911 was 352.974 as compared with 24.', 774 acres in 1910. 



The excretion of serum from moist rubber after pressing, A. Zimmkrmann 

 (Pflanzcr, 8 {U)J2), No. 7, pp. 389-39S). — In experiments conducted to deter- 

 mine a method of preventing further excretion of moisture from rubber after 

 being pressed, a method devised by D. Sandmann, wliich consists in immers- 

 ing the pressed rubber in boiling water for a short time, was found to reduce 

 materially tlie subsequent excretion of serum. The author suggests the need of 

 further experiments to determine the effect of the boiling water on the physical 

 projierties of rubber. 



Commercial creosotes with special reference to protection of wood from 

 decay, C. P. Wixsi.ow {V. S. Dept. Agr., Forcftt Serv. Cite. 206, pp. 38. fiO'f>. 

 11). — In continuation of previous investigations relative to the properties, 

 methods of analysis, etc., of various creosotes (E. S. R., 19. p. 812), tlie results 

 to date are here presented of au investigation of the quality and prices of 

 commercial creosotes. 



An account is given of the more important sources of wood-preserving 

 creosotes, methods used in their production, their general properties and the 

 quality, price, and quantity of the creosotes annually consumed in this coun- 

 try. A series of fractional distillation and index of refraction curves are 

 given for samples classed as coal-tar creosotes and mixed coal-tar creosotes. 

 Samples of a large number of authentic coal tars, oil tars, and wood tars have 

 been collected from which creosotes are being distilled and critically analyzed 

 and examined. A number of these samples are here classified and described 

 in tabular form, the data given showing the character of the oil, the fractions, 

 and the residue, together with the sulplionation residues of fractions. 



The method used in analyzing the creosotes discus.sed is appended. 



Bibliography on forestry published during 1911 (Skop.s-rardfifor. Tidskr., 

 1912, Fdckafd., No. 3, pp. 217-232). — The bibliography includes literature on 

 forestry topics published in the German. French. I-^nglish, and Scandinavian 

 languages. 



DISEASES OF PLANTS. 



The relation of certain parasitic fungi to the age and development of the 

 host plant, M. T. Cook and .1. J. T.vubkniiaus [Ahs. hi PhtilopathoJogy, 2 

 {1912), No. 2, p. 98). — According to the authors, experiments have proved that 

 laboratory inoculations made on picked fruits or detached portions of plants 

 are not sufBciently reliable for definite conclusions. It has been found that 

 there is a difference in resistance between picked fruits Ijept in the laboratory 

 and unpicked ones, and between young and older fruits of the same tree, as 

 well as between fruits of different varieties. This resistance is held to be 

 intimately associated with the cell contents of the host. It is believed that 

 GlomcrcUa rufomaculaiis of the apple is able to attack many different hosts 

 and thiit this explains the presence of so many so-called new sjiecies. 



Studies on the biology and morphology of Kuehneola albida and Uredo 

 miilleri, S. Strelin {Myeol. Ccnthl., 1 {1912), No. 5, pp. 131-137) —From his 

 investigations the author concludes that these are two developmental forms of 

 one and the same fungus. 



Notes on some heteroecious rusts of Connecticut, G. P. Clinton (Abs. in 

 Phlftopathology, 2 {1912), No. 2, p. 9//). — The author reports the teleutospore 

 stnge of Gymnosporangium japonicum for the first time in America, it having 

 been collected on two different importations of .Junipcntx chiiirmis from Japan. 

 J'eridcrmimn pcckii is shown by artificial inoculations to be the iecidial stage 

 of Pucciniasti loii mjirliUi. Pin us (nifttriacd, P. itinritinnt. and P. pondrroaa are 



