and Laboratory Methods. ^495 



some simple method of germinating seeds and growing seedlings under abso- 

 lutely sterile conditions. Large cylinders closed with cotton plugs were first 

 used, but in these the seedlings did not grow well. As this appeared to be due 

 to the complete lack of ventilation in the cylinders, various experiments were 

 made to overcome this difficulty. The final result was the apparatus shown in Fig. 

 2. The unit of this scheme is a large test tube, to which a narrow side tube is 

 joined about one-third of the length of the tube from the top — not a difficult 

 piece of glass blowing. Damp earth is placed in the test tube ; the test tube 

 and side tube are plugged with cotton, and the whole sterilized fractionally in 

 an Arnold sterilizer, or better, in an autoclav. The seeds to be used are then 

 sterilized, and one or more introduced into the tube and planted at the proper 

 depth, observing the same precautions as in inoculating a tube. After the 

 seeds have germinated, or before if desired, the side tube is connected by rubber 

 tubing with a filter pump. Air is thus drawn into the test tube through the 

 cotton plug at the top, and out at the side tube, which thoroughly ventilates the 

 growing plant. In practice we connect ten or twelve tubes with one filter pump, 

 as shown in the figure. This is about the practical limit of number, since more 

 air is drawn through the tubes nearest the filter pump than through those farther 

 away. The air circulation necessarily dries out the soil slowly, which necessi- 

 tates the occasional addition of water. This is done with sterile water and a 

 sterile pipette in the usual way. We have each had apparatus of this kind in 

 nearly continuous use for over a year, and have grown beet, cotton, rye, wheat, 

 and pear seedlings without difficulty, inoculating them with pure cultures of 

 various organisms associated with " damping off," and with specific diseases. 

 The most careful tests have shown that perfect sterility can be maintained in 

 the tubes if they are carefully plugged and the usual precautions observed. 

 Clemsoii College, S. C. Haven MetcALF. 



Botanical Garden, St. Louis, Mo. GeoRGE Grant HedgCOCK. 



A New Method of Sprouting Pollen Grains. 



To obtain preparations of sprouting pollen for class use, it is usually the 

 practice to make cultures in sugar solutions of different strengths, experiment 

 being necessary to get the most favorable concentration for each kind of pollen. 

 While this is the most common and in most cases the best method, it is not the 

 the only one that may be employed. Juranyi, for example, used the fresh cut 

 surfaces of ripe pears and got satisfactory results with the pollen of Ceratozamia. 



A method that I have used is to take advantage of nature's own medium for 

 this purpose, i. e., the liquid secreted from the stigmas themselves. It is 

 obviously not possible to make the method generally applicable, but when it can 

 be used it is not only more interesting, but also more instructive to the students. 

 The plant best fitted for this purpose, and one which is fortunately not hard to 

 obtain, is the white Bermuda or Easter Lily so common with florists in the spring. 

 The liquid secreted from the stigmas of this plant frequently collects into good 

 sized drops that can be removed with a pipette. Make a hanging-drop culture 



