Nov. i, 1885.] The Australasian Scientific Magazine. 
135 
The Germ Theory and Milk. 
Farmers have long acquired the reputation of being a steady-going, jog- 
trot people, tenacious of their supposed supreme traditional right to 
grumble, even in prosperous times, and hereditarily indisposed to change 
their ways in matters of practice, or the views in which they were reared 
that they call their convictions. Modern improvements, which have 
revolutionised our systems of farming, regarded at first even by the more 
enlightened as innovations they contemplated with concern, the farmers 
opposed as new-fangled notions they could not abide, and this expression 
of opinion was complacenty supposed to stop progress. But “ how can 
they be wise whose talk is of oxen ” only ? Had any one predicted at a 
graziers’ gathering 200 years ago that Leuwenhoeck’s looking through a 
microscope at yeast was the commencement of a series of investigations 
that would one day lead to their knowing the agent that causes 
milk to turn sour, what is the kind of reception that would pro- 
bably have been accorded to the prediction ? Would the graziers have 
subscribed to a fund for the “ endowment of research ” on so important 
a subject, or would they have regarded the speaker as so obviously trying 
to impose on their credulity that they might justiy regard him as a fit 
butt for their bad eggs ? Looking back, however, at the course scientific 
progress has taken, we see that this is what has occurred. The history is 
full of interest, and like the good old sermons of three heads under which 
farmers used to doze, it is a theme which has a practical application. As 
far back as in the writings of the alchemists of the thirteenth to the fifteenth 
■centuries we find the words “ ferment ” and “ fermentation.” The word is 
clearly from fervere , to boil, and was, without doubt, applied in the first 
place to fermentations accompanied by effervescence, produced by 
the disengagement of gas during the processes. In the course of 
time, however, it was also applied to cases where a dissolved organic body 
is modified or transformed without effervescence, as, for example, in the 
acidification of wine. We cannot ascertain clearly what exact idea was 
attached to the word “ fermentation ; ” for the word “ ferment ” is even 
applied to the philosopher’s stone. This, however, we do know — that 
these mystetious changes, brought about by some cause quite unknown, 
possessed a strong fascination for the alchemists, and that they gave much 
attention to them. Petrus Bonus, of Ferrara, in 1330, drew attention to 
the fact that a very small quantity of leaven transforms into fresh leaven a 
large quantity of paste, and likens its action to the supposed action of 
the imaginary much-sought stone. Direct and definite additions to 
knowledge about fermentation came slowly, and at wide intervals. 
