626 GROWTH OF HIGHER PLANTS 



brief discussion. Von Beke'' in 1912 described a vessel for cultivating 

 plants free from microorganisms. In common with many others, his 

 method is also compUcated. The same criticism may be offered 

 in regard to the apparatus used by Russell and Hutchinson^ and by 

 Schulow.^ The design by Schulow is most ingenious and offers many 

 advantages. 



A modification of the Russell and Hutchinson and the Schulow 

 apparatus has been used and found to be fairly satisfactory. The 

 great objection to it is the difhculty of sterilization. The apparatus 

 described in this article is a modification of the one given by Keller- 

 man^'' and has the advantage of being simple and easy to sterilize. 

 All that is required is a metal pot, a large Pyrex glass cylinder, and a 

 large beaker. No stoppers or connecting tubes are used. 



The metal pot or can of galvanized iron is made with a neck on the 

 side and a shoulder at the top to support the glass cylinder. This 

 neck serves as an opening through which to plant, to water, and 

 also to aerate. The size of the pot is determined by the kind of 

 plant to be grown. The vessel used had the following dimensions: 

 18.5 cm. tall, measured outside, and 20 cm. tall if shoulder is in- 

 cluded, 11 cm. in diameter at the base and 9 cm. in diameter at the 

 top, due to the shoulder. This shoulder is about 2.5 cm. high out- 

 side and 4 cm. inside. The pot holds about 1,700 gm. of air-dry 

 soil. At the bottom of the shoulder on the pot there are two or 

 three small holes which serve to carry ofif any water which may con- 

 dense and run down the sides of the glass cylinder. The neck on the 

 side of the pot is just below the shoulder and is about 2 cm. in di- 

 ameter and about 2.5 cm. long. The Pyrex cylinder is about 9.5 

 cm. in diameter and about 46 cm. long. The cover consists of a 

 beaker of about 11.5 to 12 cm. in diameter. These three parts con- 

 stitute the entire apparatus and involve a cost of about three dollars. 



The apparatus is simple, easy to sterilize, and can be handled 

 without special care. If soil is used it is sterihzed several times 

 in the metal pot. At the final sterilization of the soil, the glass 



' von Beke, L., Ceiitr. Bakteriol., 2te AbL, 1912, xxxiii, 442. 



8 Russell, E. J., and Hutchinson, H. B., /. Agric. Sc, 1909, iii, HI. 



9 Schulow, I., Ber. bol. Ges., 1911, xxix, 504. 



1" Kellerman, K. F., U. S. Dept. Agric, Bureau Plant Industry, Bull. 120, 1914. 



