H. B. Hutchinson and N. H. J. Miller 



189 



tion of ammonium sulphate containing 21"54 mgins. N. was added, 

 Nos. 5 and 6 were inoculated with nitrifying organisms from a liquid 

 culture, and the sterile seedlings introduced on July 4th in a slightly 

 etiolated condition. 



From the commencement of the experiment growth in Nos. 1 and 2 

 was very slow, the root growth especially being very poor. During the 

 first 3 — 4 weeks, Nos. 3 and 4 grew fairly rapidly and an abundance of 

 roots was formed. These however were not equally distributed through- 

 out the culture solution but remained in a very coiled mass near the 

 surface of the liquid. This marked toxic effect persisted for 4 — 5 weeks 

 and was subsequently followed by an even ramification of the roots in 

 all portions of the culture solution. 



On August 6th, the plants in Nos. 1 — 5 appeared healthy, while 

 that in No. 6 remained etiolated for 2 — 3 weeks and finally died off 

 A marked distinction could be seen in the colour of the plants, that in 

 No. 5 being of a much darker green than the others. From August loth 

 the plant in No. 4 began to grow much more vigorously, and the adoption 

 of a darker colour seemed to indicate infection with nitrifying organisms. 

 This would seem to be supported by the feet that both the dry matter 

 is higher and the percentage of nitrogen lower, than in the other 

 ammonium sulphate bottles. 



Table II. Wheat growing in Water Cultures. 



Series III. Peas in Water Cultures. The cultures were made in 

 WoulfF's bottles holding about 1200 c.c. water in which the following 

 amounts of the different salts were dissolved : — 



CaSO^ 



0-5 gram 



MgS04 + 7H20 0-5 



