674 Journal of Agricultural Research Vol. vi, No. 17 



(16) Loew, Oscar. 



1901. Catalase, a new enzym of general occurrence, with special reference to 



the tobacco plant. U. S. Dept. Agr. Rpt. 68, 47 p. 



(17) Mayer, Adolf. 



1886. Ueber die Mosaikkrankheit des Tabaks. In Landw. Vers. Stat., Bd. 38, 

 p. 450-467, pl- 3- 



(18) Oosthuizen, J. du P., and ShEdd, O. M. 



1913. The enzymes of the tobacco plant. In Jour. Araer. Chem. Soc, v. 35, 

 no. 9, p. 1289-1309. 



(19) SchonbEin, C. F. 



1857. Ueber chemische Bertihrungswirkuugen. In Verhandl. Naturf. Gesell. 

 Basel, T. 1, p. 467-482. 



(20) Woods, A. F. 



1902. Observations on the mosaic disease of tobacco. U. S. Dept. Agr. Bur. 



Plant Indus. Bui. 18, 24 p., 6 pl. 



PLATE XCI 



Livingstone atmometer porus cup as used for nitration. The virus of the mosaic dis- 

 ease of tobacco always lost its infectious properties in passing through this filter. 



ADDITIONAL COPIES 



OF THIS PUBLICATION MAY BE PROCURED FROM 



THE SUPERINTENDENT OF DOCUMENTS 



GOVERNMENT PRINTING OFFICE 



"WASHINGTON, D. C 



AT 



15 CENTS PER COPY 



Subscription Price, $3.00 Per Year 



V 



