PROCEEDINGS OF SECTION G. 343 
The accompanying photographs of yeasts are taken from gela- 
tine plates inoculated with the imported cultures. They pre- 
sent unmistakable evidence of impurity. We are convinced of 
the necessity of abandoning their distribution. 
Mr. Martin, Secretary for Agriculture, recognised the posi- 
tion, and issued instructions for the preparation and distribu- 
tion of pure cultures to any factory applying for them. 
To secure a pure basis we were obliged to institute an ex- 
aminati-n of our indigenous milk flora, particularly at. factories 
where the butter realised the best prices in London. 
The bacteria direct from fresh buttermilk were systematically 
examined in the leading dairying centres of the colony. Sub- 
cultures were grown and exhaustively tested. Eventually, after 
numerous trials, it was decided to select a special species of 
lactic acid-producing bacteria taken from the buttermilk in the 
Garvoc Factory. 
On the 10th June, 1899, a plate of nutrient gelatine in a 
petri dish was inoculated. A modification of Koch’s method 
of fractional cultivation was adopted. 
On the 16th June a quantity of specially selected new milk 
was sterilised, and run into a number of sterilised bottles. 
Each was inoculated direct from the petri dish pure growth. 
The bottles were suitably closed with sterilised cotton wool 
plugs and incubated at 35 deg. C.; another batch was kept at 
20 deg. C. At first the coagulum failed to form in twenty-four 
hours. Repeated inoculation was resorted to, and the coagu- 
lating power of the organism increased. The bacteria became 
more vigorous and healthy, and coagulation ensued in twenty- 
four hours at a temperature varying from 50 deg. C. to 33 
deg. C. Coagulation in every instance was less rapid at the 
lower temperatures. Constant records of the acidity developed 
were taken, and these were found to vary up to .9 per cent. 
lactic acid from twenty-four to forty-eight hours after coagula- 
tion. Later on, when the rapidity of coagulation was accelera- 
ted, an acidity of 1.2 per cent. was invariably found present. 
The acidity was estimated by the “ titration” test with an alco- 
holic solution of phenol phthalein as an indicator. At this 
point we found a cessation of fermentation. 
In the culture of this bacteria little or no gas was generated, 
in marked contrast with other lactic acid cultures we prepared. 
There was an entire absence of bitter taste and objectionable 
odour. In every case the coagulum was uniform, with prac- 
tically no separation of whey. 
Culiures have remained in this condition, afd in other 
respects unaltered for six months. 
The flavour naturally is acid, but it possesses an agreeable 
and palatable taste, with a distinctly pleasant, nutty, butter 
aroma. 
