GERM THEORY OF FERMENTATIVE CHANGES 325 
delicate character, in pairs, fours, and chains (/eptothrix filaments) as repre- 
sented at ain Plate XII. The milk examined was in a wine-glass into which 
it had been poured from the bottle, and this was kept covered till 5 p.m. when 
a small drop was taken out for inoculation of one of the glasses which we may 
term Boiled Milk I. It was now more sour to the taste, and more sharply acid 
to litmus, and when diffused between plates of glass exhibited small white 
masses which the microscope showed to be granular (deposited caseine) while the 
motionless bacteria before observed were again seen in abundance. The glass 
also contained some larger portions of soft curd. Next day at 8.30 a.m., or 
fifteen and a half hours after inoculation, Boiled Milk I, though unaltered in 
appearance, had communicated a faintly sour smell to the air under the glass 
shade, while the smell of boiled milk was gone. A drop removed by pipette 
reddened litmus more than on the previous day, though still faintly blueing 
red paper, and under the microscope motionless bacteria were seen in consider- 
able numbers exactly similar to those observed in the unboiled milk, except 
that there was greater variety in their size, some being considerably larger, as 
shown in the plate at 6. At 5 p.m., twenty-four hours after inoculation, the 
glass shade gave a pleasant smell of slightly sour milk, and the reaction was 
sharply acid, but the milk was still fluid, and next morning rather more than 
thirty hours after inoculation the milk had set into a solid mass. 
On the same day (August 15) that Botled Milk I was inoculated as above 
mentioned, parallel experiments were made with turnip infusion and with 
urine, each of which received a minute drop from the same glass of sour milk. 
The turnip infusion was from the stock prepared in February, having both 
naked-eye and microscopic appearances unchanged ; and the urine was a glass 
prepared at the same time as that used for Bactertum No. II, retaining un- 
impaired in every respect the characters which it then had, seventeen days 
before. Neither of these glasses showed any signs of bacteric development on 
the 16th, the day after inoculation, but on the following day both were mani- 
festly nebulous, and both exhibited under the microscope numerous motionless 
bacteria. There was, however, a remarkable difference between the organisms 
in these two glasses. In the turnip infusion the bacteria did not differ very 
greatly from those in the boiled milk, except that the leptothrix form was very 
seldom seen, and that the segments of the pairs were sometimes of greater 
length, while unjointed specimens, also pretty long, made their appearance, 
as atc. In the urine on the other hand the deviations from the form in the 
milk were most remarkable, as will be sufficiently evident from an inspection 
of the plate under Urine I. Some indeed, like d, were not very different from 
the original leptothrix form, but even such specimens often exhibited, as that 
