DISEASES OF PLANTS. 1137 



gave 9.5 per cent pure rubber on a water-free basis, or, taking the mill weight 

 of the material as a basis, S per cent. Inspection of the material prepared for 

 analysis showed that the trunks were made up of 40.4 per cent bark and 53.6 

 per cent wood. Determinations made of 2 whole i)lants gave 54.6 and 57.8 

 l»er cent of bark, resi)ectively. 



[Rubber tapping experiments and mechanical tests of several Surinam 

 woodsl, W. A. Van Asbkck {Dcpt. Landb. Hurinainc liul. /J. pi). 11). — This 

 bulletin contains the results of tapping experinjents conducted with Jlcvea 

 .^/(///a»r/(.s(.s' in 1008, including analyses of samples of the rubber, and notes on 

 their valuation by diflerent commercial firms. Data are also given on me- 

 chanical tests made with 5 Surinam woods. 



The direct utilization of latex in the industries, L. Morisse (Le Latex: 

 Son UtUmition directe dans Vlndustrie. Paris, 190S, pp. 68J/, figs. 17). — This 

 work is offered as a resume of the present state of our knowledge relative to 

 latex. It consists of an exposition of the advantages of the author's secret 

 process of coagulating latex, whereby the coagulated latex may be used directly 

 for manufacturing purposes without first being converted into crude rubber. 

 All of the author's early and recent papers on the subject of harvesting and 

 coagulation of latex are included, together with the reports of the purely scien- 

 tific latex investigations made by the author's two principal collaborators, V. 

 Henri and G. Vernet. 



DISEASES OF PLANTS. 



A method of checking' parasitic diseases in plants, M. C. Potter (Jour. 

 Agr. Set., 3 (1908), No. 1, pp. 102-107).— The author has i)reviously shown 

 (E. S. R., 13, p. 467) that the organism causing the white rot of turnips owes 

 its power to the fact that it secretes an enzym which acts upon the cellulose, 

 dissolving the middle lamella and effecting the disintegration of the cell wall, 

 while at the same time it produces a toxin fatal to the protoplasm of its host 

 cell. Subsequent studies with this organism { I'sciuhjinontts dcstructans) have 

 showed that it is possible that the toxin may be one of the waste products of 

 bacterial metabolism. 



In a series of investigations, the author grew the organism in cultures, and 

 after considerable growth was made he sterilized the media, filtered it, and 

 steamed it, thus destroying the enzyms and all organisms present. Turnips 

 were then inoculated with the organism causing the white rot, and the pre|)ared 

 toxic solution was emi)loyed to determine whether it would check the rot after 

 it had once become well advanced. Cultures were allow-ed to develop for sev- 

 eral (lays, after which the toxic solution was plactnl on one half of an inoculated 

 turnip, the other half remaining as a control. On the half receiving the toxic 

 substance the growth of the organism ceased. Where weaker solutions were 

 used the bacteria were found to l)e unable to grow in the solutions and they 

 prevented further extension of the rot. The toxic solution prepared from the 

 turnip was found not to be necessarily destructive of other organisms. 



Some investigations were conducted to determine whether this curative prin- 

 ciple would apply in other direction.s, and cultures were made of PcnicHUum 

 ilitUciim and /'. olirarcuni, which cause the rapid rotting of oranges and 

 lemons. These fungi were grown in sterilized orange juice, and after prepara- 

 tion of the toxic sul)stance a number of oranges were inoculated with the 

 fungus. A few days later, when tlie characteristic color of the rot had ap- 

 peared, the oranges were treated with the toxic .solution and no further decay 

 was noticed. 



8S800— No. 12—09 4 



