80 TWELFTH REPORT. 



a', with a cotton filter, b'. To the third tube of cock, A, is attached 

 another small flask, D. In addition to the flanged tnbe, a", with its cot- 

 ton filter, b'^, it has a third tube, c, entering it. This tube is drawn to a 

 point, dips to the bottom of the flask, and is bent so as to end in the 

 angle between the side wall and the bottom of the flask. Tube, C, is 

 connected wath cistern, E, which in turn is connected with an aspirator. 

 Flasks A, C, and D are supported on a low ring stand. 



The apparatus is operated as follows: Flask A is filled with dis- 

 tilled water; into flask C is put 25 cc. of agar medium; and E is dis- 

 connected after the rubber tube between D and E lias been closed by 

 means of a clamp. The whole apparatus (except the cistern) is then 

 placed in the autoclave and sterilized. After autoclaving, flask C, while 

 still attached to the ringstand, is introduced through a slot into a large 

 cardboard cylinder. Around the arm supporting- flask C, is packed 

 sufficient cotton to close the opening in the cylinder. The agar medium 

 in the flask is kept at about 45° C. by means of an electric bulb placed 

 inside the cylinder. D and E are again connected. When the apparatus 

 has cooled sufficiently, the rubber stopper is removed from flask D, the 

 seeds and the desired disinfectant are quickly introduced, and the flask 

 is again closed tightly. Flask D is then thoroughly shaken, so that the 

 disinfectant may come in intimate contact with the walls of the flask, 

 the tube and the rubber stopi)er. This is to destroy any spores that may 

 have happened to enter when the flask was opened to admit the seeds 

 and disinfectant. When the seeds have been in the disinfectant the re- 

 quired length of time, the disinfectant is drawn off into the cistern E, 

 by means of tube c. The last drops can readily be removed by tilting 

 flask D. Water is then drawn through cock B from flask A into flask 

 D, upon the seeds. This is done by exhausting the air in cistern E. To 

 prevent the air from entering flask D during this process, a rubber 

 finger-cot can be drawn over b" or the finger may simply be pressed 

 down on it. In that way the seeds can be washed as frequently as de- 

 sired. After washing them, some of the agar medium is drawn from 

 flask C by turning cock B so as to connect C and D. Agar solidifies 

 at 42° C. It is therefore kept at about 45° C until needed. That tem- 

 perature will not harm the fungi or bacteria that may adhere to the 

 seeds. Sufficient agar to cover the seeds is introduced. The rubber 

 tubes between D and B and between D and E are closed by means of 

 clamps. The rubber tubes are cut beyond the clamps and flask D is 

 ready to be set aside to incubate. » 



In all of the following germination experiments, all of the seeds were 

 carefully inspected so as to obtain only perfect specimens. In all the 

 germination experiments, each lot consisted of twenty-five seeds. The 

 germination percentage, under ordinary laboratorv^ conditions, of the 

 seeds in the following experiments was as follows: Lupine 90%, Pea 

 96%, Wheat 90%, Corn 100%, Mustard 90%. The first agent used in 

 treating the seeds w^as cleaning fluid (HoSO^+KoCr^O-). As far as I 

 have been able to ascertain it has not been employed for the purpose 

 before. It occurred to me that cleaning fluid might be a very desirable 

 agent to use since it penetrates no farther than it thoroughly oxidizes. 

 Thus, by timing its action, we can destroy as much of the seed-coat 

 as is safe under any given conditions, and also the adhering fungiis 



