112 
PROFESSOR. P. F. FRANKLAND AND MRS. G. C. FRANKLAND ON 
The readiest means of inducing nitrification in suitable anirnoniacal solutions is, as 
is well known, by the introduction of a minute trace of ordinary garden soil. The 
solution we employed for the purpose had the following composition :— 
Salt solution* .... 
Ammonium chloride 
Carbonate of lime (pure) . 
100 c.c. 
•5 grm. 
o'O grms. 
>Diluted to 1000 c.c. 
The solution was thus entirely free from organic matter, as the results of pre\dous 
investigators had clearly indicated that nitrification can take })lace in purely 
mineral solutions, whilst we hoped, through the absence of oig-anic matter, to eliminate 
such other forms as require the same for their growth and mulliplication. 
The solution was invariably placed in small G oz. medicine bottles, which were filled 
to a depth of 2-3 inches, the bottles being previously plugged with cotton-wool, and 
sterilised at 150° C., whilst after introducing the liquid, the whole was steam- 
sterilised for upwards of an hour on three successive days. 
Five bottles of this description were inoculated with a minute quantity of garden 
soil on May 9th, 1887, and placed in an incubator at 30° C. 
On examination afcer eleven days, the bottles were all of them turbid, exhibited a 
slight skin on the surface and yielded the characteristic reactions for nitrous and 
nitric acids. Three of these solutions, which had nitrified, were submitted to gelatine 
plate cultivation ; the plates developed numerous colonies, many of which caused 
liquefaction of the gelatine. A number of different colonies were picked out with the 
steidle platinum needle, and individually inoculated into separate bottles containing 
the sterile ammoniacal solution, but not one of these yielded any niti'ous or nitric acid 
on subsequent examination after suitable incubation. 
From one of the original bottles which had nitrified after addition of garden soil, a 
second bottle of ammoniacal solution was inoculated with a platinum needle; when 
this bottle had undergone nitrification, a fresh bottle was similarly inoculated from it, 
and so on in a long series of generations. The dates of inoculation of these successive 
generations, with other particulai's, are recorded in the following table 
* Tliis salt solution was prepared by dis.solving 1 grm. of pota.ssinm plio.spbate, '2 grm. of ci’jstab 
lized magnesium snlpL.ate, and '1 grm. fused calcium chloride in 1000 c.c. of water. 
