211 



upon the errors and evils wliieli result from neglect to observe this 

 principle, and at the same time pointed out the great ditticulties in 

 observing it pro])erly. He also urged the danger of hasty inferences 

 and the need of repeating experiments. 



Dr. Morgen of the Halle Station cited the results of extended experi- 

 ence and experiment in the detection of adulterants, especially Redonda 

 ])hosiihate, in Thomas slag. The determination of loss on ignition is 

 often helpful, a loss of 0.5 to 1 per cent indicating adulteration. The 

 specific gravity method of Loges is also valuable, but instead of 

 potassio-mercuric iodide solution for detecting Eedonda x)liosphate, 

 Br. Morgen reconnnended bromoform (sp. gr. 2,9). The method of 

 Eichter for separating Redonda phosphate from Thomas slag by dilute 

 soda solution is excellent. Five per cent solution of citric acid dis- 

 solves Thomas slag, but not Redonda phosi^hate. The method of 

 Jantsch and Schucht is one of the best for quantitative determinations 

 of Thomas slag. 



Dr. Cluss of the Halle Station cited some interesting experiments 

 on the use of hydrofluoric acid as an antiseptic in the manufacture of 

 alcohol. It prevents souring and promotes the fermentative action of 

 yeast in a very marked degree. 



Dr. Wilfarth of the station at Bernburg described a germination 

 apparatus for testing seeds, especially of sugar beets. It consisted of a 

 brass sieve, the bottom of which was covered with muslin. On this 

 were placed the seeds and over them another piece of nnislin was laid. 

 This latter was covered by a layer of sand, which was kept moist. 



Professor Drude of Dresden and others gave the results of experience 

 with fungicides on potatoes affected by Peronospora viticola. 



A paper Avhich excited especial interest was one by Dr. Gilbert on 

 root tubercles and the fixation of atmospheric nitrogen by plants. It 

 was a preliminary notice of methods and results of a large number of 

 experiments at Rothamsted with annual and perennial legumes groAvn 

 in sterilized sand and in rich soil, without nitrogenous fertihzers, and 

 with and without inoculation by microbe seeding. A luimber of photo- 

 graphs showed the development of the plants and of the root tubercles. 

 The inoculated i^lants had a1)undant root tubercles, grew vigorously 

 without nitrogenous fertilizers, and gained large quantities of atmos- 

 pheric nitrogen. The connection between this acquisition and the root 

 tubercles was perfectly evident, thus confirming observations of other 

 exijerimenters. Esj)ecial attention was called to the develoijment of 

 root tubercles at different periods of growth of the plants and to marked 

 differences between the annuals and perennials. The author has fur- 

 nished an abstract for the Experiment Station Record. 



In the discussion which followed the reading of Dr. Gilbert's paper, 

 Professor Hellriegel, who was the first to show the connection between 

 the root tubercles and the fixation of nitrogen and whose results it was 

 one purpose of Messrs. Lawes and Gilbert's experiments to confirm, 



