426 BOTANICAL GAZETTE [june 



and by Wernicke (30) in 1895 for several different kinds of seeds. 

 Mention may also be made of the work of Jarzymowski (17) in 

 1905 with seeds of various economic legumes, and of Bolley (3) 

 in 191 2 with those of alfalfa. Bolley obtained positive improve- 

 ment in germination if exposure to a given temperature was not 

 long enough to kill the embryo. 



Treatment with concentrated sulphuric acid dates from the 

 work of Rostrup (25) in 1896-1897. It was also used by Todaro 

 (29) in 1901, by Hiltner (14) in 1902, by Jarzymowski (17) in 

 1905, and by Bolley (3), and Love and Leighty (22) eight years 

 later. Increased germination was obtained in all these cases. 



Treatment with other chemicals has included the use of ether, 

 ethyl, and other alcohols (Verschaffelt 31, 191 2), chloroform, 

 sodium hydroxide, postassium hydroxide, potassium nitrate, and 

 mercuric chloride. Of these, the lower alcohols are the only ones 

 that are very effective. 



There are obvious practical objections, however, to the use of 

 either hot water or chemicals. As a consequence, there have been 

 numerous efforts to devise means for the mechanical treatment of 

 hard-coated seeds. In Germany, Kuntze and Huss (16), working 

 about 1890, were able with a scratching machine to increase the 

 germination of Latkyrus sylvestris 83 per cent, Vicia Cracca 71 per 

 cent, and Astragallus Glycy phyllos 77 per cent. 



Somewhat later Michalowski devised an apparatus in which 

 the seeds were passed between two rollers, one of rubber, the other 

 of rough steel. Smaller sorts of seeds were badly crushed by such 

 a mechanism, and it was later displaced by two others, one designed 

 by the Wissinger Seed Co., of Berlin, the other, called a "prepara- 

 tor," by H. Nilsson of the experiment station at Svalof, Sweden. 

 In both of these the seeds are thrown from a revolving disk against 

 the concave surface of a circular rough stone, within which the 

 disk revolves. Hume and Garver (15), using the "preparator," 

 obtained a definite increase in the germination of seeds of Medicago 

 sativa, M. media, and M. falcata. Another machine now in use in 

 England has made it possible, according to Carruthers (7), the 

 designer, to buy clover seed guaranteed to germinate 98-100 per 

 cent. The seeds to be treated are fed into a revolving cylinder 



