SOILS AND FERTILIZERS 523 



Pollen is the powdery substance, usually yellow or brown, which 

 falls from flowers when they are shaken. 



Pollination is the act of conveying pollen to the part of the 

 flower prepared to receive it. Pollination may be brought about 

 either by natural agencies, such as wind, insects, etc., or by artificial 

 means. 



Self-fertile plants or varieties are those which do not require 

 pollen from other plants or varieties in order to produce seeds or fruit. 



Self-sterile plants or varieties are those which do require pollen 

 from other plants. 



Lactation is the formation or secretion of milk. The period 

 of lactation as applied to cows means the length of time since calving 

 that they have been giving milk. 



Authorities Consulted. F. Bs. 44, 48, 56, 77, 192, 245, 278, 

 286, 315, 398; Bu. Pit. Ind. Bs. 1, 22, 51, 63, 71, 76, 134, 404, 441, 

 692; Bu. Soils Bs. 55, 58, 62, 67, 69, 76; Y. B. 1909; Ala. Ag. Dept. 

 Bs. 9, 10, 2; Univ. Ariz. B. 45; Ark. E. S. B. 46; Calif. Univ. Bs. 

 23, 157, 173, 179, 187, 194; Colo. Ag. Col. Bs. 99, 115, 168, 178, 

 179; Conn. E. S. Repts. 1900, 1902, 1903, 1905, 1906, 1907, 1908; 

 Del. Ag. Col. B. 60; Fla. E. S. Bs. 2, 10, 20, 50; Ga. Ag. Col. B. 72; 

 Pur. Uni. Bs. 10, 18, 88, 92, 106; Uni. 111. Bs. 94, 109, 115, 116, 129, 

 130, 140, 160; La. E. S. B. 31; Md. E. S. Bs. 122, 126, 151; Mass. 

 E. S. Bs. 51, 137; Mass. Ag. Col. Bs. 9, 10, 14, 18, 81, Special B., 45, 

 94, 102; Kept, Mass. E. S. 1907; Md. E. S. Bs. 110, 122; Mich. E. S. 

 B. 11; Mich. Ag. Col. B. 231; Miss. E. S. B. 99; Md. E. S. B. 128; 

 N. H. E. S. Bs. 5, 12, 13, 21, 140; N. H. Ag. Col. Bs. 26, 83, 88, 108; 

 Cornell Univ. Bs. 7, 201, 241; Cornell R, C. 9; N. Y. E. S. Bs. 192, 

 205, 206; Univ. Minn. B. 34; N. C. E. S. Kept. 1887, B. 77; O. E. S. 

 Bs. 54, 59, 69, 79, 83, 114, 124, 134, 167, 125, 141, 159, 161, 168, 172, 

 183, 182, 184, 206; Ore. E. S. B. 79; Pa. Ag. Col. Bs. 35, 49, 54, 63; 

 Clemson Ag. Col. Bs. 4, 12, 15, 18, 21 ; Univ. Tenn. Bs. 1, 3, 86, 92 ; 

 Univ. Tenn. Rept. 1899; Tex. E. S. Bs. 85, 107, 112, 115, 84, 138; 

 Univ. Vt. B. 154; Va. E. S. B. 187; W. Va. E. S. Bs. 28, 40, 51, 80; 

 Univ. W. Va. Bs. 97, 99, 101, 112, 114; Wash. E. S. Bs. 19, 32, 37; 

 Wash. Ag. Col. B. 98; Univ. Wis. B. 180; Univ. Wyo. B. 44; R. I. 

 E. S. Bs. 71, 90, 95, 96, 104, 114, 106, 118, 129, 142, 143, 147; Ont. 

 Agr. Dept. Bs. 164, 169. 



PLANT INOCULATION. 



Plant inoculation for the restoration of nitrogen to exhausted 

 soils is comparatively a recent discovery. In fact the whole science 

 of bacteriology is comparatively new. When Dr. Rudolph Virchow 

 announced a few years ago that the diseases of the human body are 

 the results of an injurious environment of the body cells, he laid the 

 foundation of the science of bacteriology. Dr. Louis Pasteur put 

 forth the theory that fermentation is caused by germs in the air. Dr. 

 Emil Roux, another advocate of the germ theory, discovered and 

 identified the bacillus of diphtheria and a serum for the cure of that 

 disease, receiving in 1903 the Osiris prize of $4,000. Another la- 

 borer in the field of bacteriology, Dr. Metchnikoff, advanced the the- 

 ory that the apparent old age of men and women is caused by the 



