14 N. H. AGR. EXPERIMENT STATION [Bulletin 208 



subsequent periods of observations. The addition of the .05 per cent gela- 

 tine greatly increased the adhesiveness of both the basic and neutral salts, 

 the more marked effect being produced upon the latter. 



The Action of Stjlphurt Fungicides. 



The nature of the action of sulphur fungicides is coming to be more and 

 more of a critical problem, particularly in regard to the control of apple 

 scab; and W. L. Doran (Botany) has pursued during the past year a study 

 of the conditions under which these fungicides are toxic to parasitic fungi. 

 It was found that sulphides are extremely toxic, but that since the poly- 

 sulphides decompose rapidly on drying their value is merely a contactual 

 one. Data were gathered on the relation between temperature and the 

 time required for sulphur to kill, and it was found that sulphur was more 

 active at high than at low temperatures. Sulphur was found to be toxic 

 only when it acted in the presence of oxygen. 



Plant Metabolism Studies. 



The relation of nutrition to fruit production has received a great deal of 

 attention during the past few years, particularh- among horticulturists, 

 who have given special attention to this problem in its relation to the apple. 

 H. R. Kraybill and T. O. Smith have been studying the effect of varying the 

 supply of nitrogen, phosphorus and sulphur upon growth and fruit produc- 

 tion, using the tomato plant in all of the work. As mentioned in the last 

 report two sets of plants have been grown in sand in the greenhouse. The 

 first set consisted of four lots of plants receiving the followmg nutrient so- 

 lutions: lot 1, complete nutrient solution; lot 2, nutrient solution without 

 nitrogen; lot 3, nutrient solution without sulphur; and lot 4, nutrient so- 

 lution without phosphorus. The second set was a duphcation of the first 

 set except that an additional lot was grown with a very small amount of 

 phosphorus in the nutrient solution, and grown at a different season of the 

 year. Samples of the leaves and stems of the plants were preserved for 

 analysis. The work during the past year has dealt entirely with the analysis 

 of these samples. 



Samples of plants gro^vTi under each treatment were preserved with al- 

 cohol and CaCOs. Free reducing substances, sucrose, maltose, starch and 

 acid hydroUzable material were determined in each of these samples. Other 

 samples are being analysed by the Koch method of tissue analysis, which 

 consists of separating the sample into three fractions as follows: Fi Lipoid 

 fraction, F2 water and 80% alcohol solution fraction and F3, the water and 

 alcohol insoluble fraction. The nitrogen distribution of these fractions 

 is being studied; and if sufficient material is at hand, the phosphorus and sul- 

 phur distribution will also be included. 



