224 NUTRITIVE METABOLISM 



Before placing in position the jar should be cleaned with nitric 

 acid, and washed out with distilled water, then rinsed with cor- 

 rosive sublimate, which should also be thoroughly washed out 

 with distilled water. The culture solution should be poured in 

 until it reaches to within 2 cm. of the top. The conditions for 

 light and temperature may be made fairly normal if the jars are 

 set deeply in a large box containing soil. The plants should be 

 removed from the jars every ten days and the latter should be 

 rinsed out with distilled water and refilled with fresh solution. 

 During this process the plant, which is attached to the top, should 

 be set over a similar jar containing distilled water. The tempera- 

 ture of the air should be made suitable for the species tested. 



The plants should be grown in a solution containing all of the 

 indispensable elements, and in others from which certain ones are 

 lacking. The different solutions may be made up as below, and 

 kept in tightly stoppered bottles, in darkness, and then diluted 

 with distilled water in the proportion of 10 parts of the solution 

 to 48 of water. The following solutions are those used by 

 Schimper 1 and will suffice to carry a single series of simple 

 tests. It will be found possible to carry the plant to maturity in 

 the normal solution and this should be done if convenient, for 

 the purposes of comparison with those grown in incomplete solu- 

 tions. 



Normal Solution. 

 "6 g. calcium nitrate. 

 ~"~i 1.5 g. potassium nitrate. 



1.5 g. magnesium sulphate. 

 - ,1.5 g. neutral potassium phosphate. 



1.5 g. sodium chloride. 



600 cc. distilled water. 



Solution Lacking Calcium, v 

 7 g. potassium nitrate. 

 1.5 g. magnesium sulphate. 



1 Schimper, A. F. W. Zur Frage der Assimilation durch die grilne Pflanze. 

 Flora. 73 : 207. 1 890. 



