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PROFESSOR P. F. FRANKLAND AND MRS. G. 0. FRANKLAND ON 
although this j)roperty does not serve to distinguish it from the other organisms which 
accompanied it until the final separation by the process of dilution was accomplished. 
(3) On microscopical examination, the solutions nitrified by the pure culture . 
exhibited numerous small bacillar forms, which stain with somewhat more difficulty 
than most micro-organisms. The bacilli are about 0'8/x in length, and hardly longer 
than broad, in fact, their form is intermediate l)etween that of a bacillus and micro¬ 
coccus, so that the term “ bacillococcus ” may not Inappropriately be used to designate 
them. They occur )3oth isolated, in pairs, and in small irregular groups. 
The accompanying figure exhibits their appearance as taken from bottle No. 1 
itself 
Fig. 1. 
Thus tlieir appearance, although not so characteristic as to admit of their ready 
detection when present in small numbers along with other organisms, is still 
sufficiently definite to enable them to be distinguished from many other forms. 
The organisms in the living state exhibit vibratory movement only. 
Quantitative Determination of Nitrification. 
We have already pointed out how necessary it is in speaking of nitrification, to 
indicate cpiantitatively the extent to which the process has taken place, to insure 
that the slight traces of nitrous and nitric acids so frequently exhibited by water 
which has been in contact with the air have not been mistaken for true nitrification. 
We have, therefore, quantitatively determined the condition of the mineral nitrogen 
in several of the solutions in question. In these quantitative determinations we have 
employed the methods previously described by one of us (‘Chem. Soc. Journ.,’ vol. 53, 
p. 368). 
Thus the ammonia was determined by means of Nessler’s reagent, and com¬ 
parison of the tint produced with that obtained with a standard solution of 
ammonium chloride. In determining the nitric acid, the nitrite was first destroyed 
by evaporating the solution with an excess of ammonium chloride, and then decom¬ 
posing tlie residual nitrate witli sulphuric acid and mercury, the nitric oxide evolved 
being carefully measured in a gas-analysis apparatus. 
In the determination of the nitrous acid, on the other hand, tlie solution was 
evaporated to dryness, with a little pure caustic soda, to prevent the loss of nitrite 
by decomposition with ammonia present; the residue was then decomposed with urea 
and dilute sulphuric acid, tlie gas evolved (consisting of nitrogen and carbonic anhy¬ 
dride) was freed from carbonic anhydride by means of strong caustic soda, and the 
residual nitrogen was then carefully measured in the gas-analysis apparatus. 
