Journal of Agricultural Research 
Vol. VIII, No. 8 
318 
(5) Headden, W, P. 
Arsenical poisoning of fruit trees. Colo. Agr. Exp. Sta. Bui. 131, 27 p., 
7 pi. 
Arsenical poisoning of fruit trees. Colo. Agr. Exp. Sta. Bui. 157, 56 p., 
illus. 
The fixation of nitrogen in some Colorado soils. Colo. Agr. Exp. Sta. 
Bui. 155, 48 p., illus. 
Nitrates in the soil. Colo. Agr. Exp. Sta. Bui. 160, 8 p. 
The fixation of nitrogen in some Colorado soils. A further study. Colo. 
Agr. Exp. Sta. Bui. 178, 96 p., 6 pi. 
(10) Swingle, D. B., and Morris, H. E. 
1910. A preliminary report on the effects of arsenical compounds upon apple 
trees. In Phytopathology, v. 1, no. 3, p. 79-93, pi. 16-17. Biblio¬ 
graphical footnotes. 
(11) Whipple, O. B. 
1907. Western Slope fruit investigation, 1906. Colo. Agr. Exp. Sta. Bui. n8 f 
16 p. 
1908. 
( 6 )- 
I9IO. 
( 7 ) - 
I9IO. 
( 8 ) - 
1910. 
( 9 )- 
1911. 
