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Latest Conquest . 
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stances, of setting up changes in living animals and plants. 
They are drawn into the lungs with the breath ; they enter 
the stomach with the food ; and in these organs, or in the 
blood, they set up changes which may be likened to fer- 
mentation. That in this manner fevers, cholera, smallpox, 
&c., are propagated in man, pebrine in silkworms, “charbon ” 
in cattle, may be considered proved beyond all doubt. 
We know it has been asked why, if such be the case, are 
not all persons attacked by fevers, &c. ? The answer is, 
firstly, that the “ germs ” of those diseases are not equally 
present either in time or space. During the epidemics of 
cholera or plague a very large part of the persons in the 
districts affecfted, sometimes even a majority, are attacked. 
Again, climatal and seasonal conditions vary : the germs of 
yellow fever do not seem capable of reproducing themselves 
in the British Islands, whilst those of smallpox, diphtheria,* 
and scarlet fever find no difficulty in crossing the Arctic 
circle. Lastly must be considered the personal element. 
Some men have evidently a greater power of resistance than 
have others. If exposed to infection they take the disease 
slightly, or not at all. The case is precisely similar with 
ordinary fermentation. The brewer seeks to have his worts 
always in the same condition, and to effedl the fermentation 
in one unvarying manner ; yet sometimes in spite of all his 
tadf and experience, aided by all the resources of modern 
science, a brewing fails. Need we then wonder if, in the 
vastly more complex field within which disease germs a <51, 
the results should vary ? 
A certain writer whose works we lately noticed, and who is 
disposed to be very severe on our medical men, and upon the 
“ germ-theory” as the fashion of the day, thinks that rinder- 
pest and other cattle diseases would disappear if cattle were 
kept under better sanitary conditions. Unfortunately it has 
sometimes happened that cows were attacked on model 
farms, where every care was taken for ventilation, drainage, 
cleanliness, and pure water, whilst the disease passed harm- 
lessly over others which were housed and kept in the filthiest 
and most slovenly manner. 
But we must hurry on to our more immediate subject. 
Phthisis — or, as it is commonly called, consumption — is of 
all diseases the commonest and the most hopeless. That it 
carries off about one-third of our adult population, or rather 
of those who have reached the age of puberty, is admitted. 
* During the past month diphtheria has been very severe in the Loffoden 
Islands. 
