186 TEANSACTIONS OF THE HORTICULTUKAL 



that the nitrate salts were a product of certain organisms of the soil 

 whose province seemed to be to work over the organic nitrogen of 

 the soil, manures, etc., into a nitrate form, and so in a condition to 

 be utilized by the plant. 



The experiments conducted by Prof. Burrill and myself, at the 

 laboratory of the State University, began with an attempt to isolate 

 the numerous organisms of the soil, and determine, if possible, which 

 kind or kinds did this special work of nitrification. 



The organisms thus far isolated and tested as to their special 

 function in decomposing organic matter, have thus far performed a 

 very different work from that of nitrification, though a work of no 

 less importance. In the two species so far isolated, they have per- 

 formed the first step in the process — that of converting the nitrogen 

 of the organic matter on which they feed, into ammonia. This step 

 in the process is a highly essential one, because always the first one. 

 It is not yet determined whether these same organisms go on and 

 carry the process through the nitrous to the final nitric stage, or not. 

 Further experiments are necessary to determine if these or some 

 other forms go on and complete the work of nitrification. 



The question may be asked here, if we have ourselves any proof 

 of the nitrifying effect of soil organisms. The experiments of 

 Warrington would seem to be quite conclusive, and have been veri- 

 fied in our own work in a very different, and quite as conclusive a 

 manner, as follows: 



A pot of ignited sand, free from all foreign matter was pre- 

 pared. Some ripe pea-pods, fresh from the garden, procured and 

 washed in a strong solution of corrosive sublimate to destroy all 

 germs. The pods were then opened and the seeds thus quickly 

 conveyed to the sand with the least possible chance of carrying 

 with them any organism. As a further precaution the sand was 

 watered with chlorinated water, which has the property of de- 

 stroying all organisms, and is at the same time a decided stimulus 

 to germination of seeds. 



On the thii'd day the seeds were sprouting vigorously, no organ- 

 isms being present. 



By the fifth day the progress of growth seemed to be feeble, 

 but the chlorinated water having been discontinued, and proper nu- 

 triment solution having been supplied, together with a small lump 

 of soil to stock with organisms, the growth of the seeds seemed to 

 revive — the water filtering through the sand wa=^ becoming turbid 

 with bacteria. A chemical examination of this drain-water showed 

 the nitrates to be still absent, care having been taken to make up 

 the nutriment solution free from any nitrogen in the form of ni- 

 trates. 



On the sixth morning the drain-water was densely stocked with 

 organisms of several sorts, as shown by a microscopical mount 

 made at the time. But most interesting of all, we find now a posi- 



