342 QUEENSLAND AGRICULTURAL JOURNAL. {1 May, 1899. 
on sounding the hole some time after the first charging, finds that the salt 
has been absorbed, he then recharges, and when the second lot is absorbed he 
must ringbark the tree and wait until it dies before firing. In the case ofa 
hollow tree, as before stated, the hole should only be bored into the solid wood, 
otherwise the effect will be lost, as the salt will pass into the hollow instead of 
being carried to the extremities of the limbs and roots by the circulation of the 
sap. . 
With large hollow stumps, Mr. Mac Mahon advises that the hollow be 
filled with saltpetre, and then covered with a slab or sheet of bark. When 
the whole of the salt has disappeared, the stump when fired will burn out to 
the extremity of the longest roots. Mr. Mac Mahon, however, prefers the use 
of dynamite, as being more expeditious. Where time is of no importance, the 
saltpetre method has decided advantages. 
Our correspondent states that he wishes to get rid of heavy hardwoods. 
We, of course, do not know how far from the North Coast Railway line his 
Jand is situated, nor what kind of roads exist leading inland from Pinbarren 
Siding, but we might suggest that good sound hardwood—pntting white gum 
out of the question—should rather be protected than destroyed. A few 
hundred acres of timber suitable for the sawmill are a good legacy to leave to 
the future generation, especially so near to Gympie and Brisbane. We would 
ask our correspondent to study our articles on ‘Forest Conservancy” before 
doing away with timber which will require several generations to reproduce. 
Dairying. 
RIPENING OF CHEESE. 
Burren is at its best, so far as food purposes are concerned, immediately it is 
made, while with cheese the case is much different. When the manulacture 
of cheese has been completed, it is still an unpalatable product, and one that 
is unsuitable for human use. Before it should be used as food it must be 
changed materially from a physical as well as from a chemical point of view. 
These changes are controlled in large parts by the action of biological forces, 
and while our knowledge concerning them is still far from being complete, yet 
enough is now determined to justify a consideration of the same from our 
present standpoint. : 
During the last year Dr. 8. M. Babcock and the writer (H. L. Russell, 
Professor of Bacteriology, Wisconsin College of Agriculture) were able to show 
that the generally accepted theory, that the ripening or curing of cheese was 
‘produced solely by the action of bacterial forces, was erroneous. As a result 
_ of this work, it is our belief that the ripening of cheese is a twofold problem 
that may be divided in the following way :—First, there is the breaking down, 
or the peptonisation of the green eurd into the ripened cheese, and, second, 
there is a gradual development of the peculiar flavours that characterise the 
various kinds of cheese. ‘These two phases of the problem are quite distinct, 
and must be investigated in a different way. J'urthermore, we have found 
that the breaking down of the casein is produced, not by the action of bacteria — 
in the cheese, but by the presence of certain peculiar chemical ferments, known 
as enzymes, that are inherent.in the milk itself, and which are produced directly 
by the animal, and not by the operation of bacterial changes in the milk. The 
ferment causing this decomposition of the casein is called galactase, and so far 
as our researches have been made with the milk of different species of animals, 
including the human, we have found this unorganised ferment present in all 
milk. 
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