JANUARY 25, 1901.] 
forms of life roughly classified as ‘ ani- 
malcules.’ These were either not present 
at all in the alcoholic fermentation or, if 
present, were fewinnumber. Moreover, in 
this case also, the microscopic life seemed 
to be a consequence rather than a cause 
of putrefaction, inasmuch as it was most 
abundant, not at the beginning, but toward 
the end of the process. Meat keptin warm 
air or warm water soon ‘ spoiled,’ though ex- 
actly how or why no one knew. Chemical 
changes were obvious and abundant, but of 
a totally different kind from those character- 
izing the fermentation of alcohol or vinegar. 
Organic decomposition and decay, two of the 
most widespread and universal processes in 
nature, while occurring on every hand, 
were in the early part of our century either 
not understood or else incorrectly inter- 
preted. The slow decay of timber and of 
teeth, the rapid decay of fruits and flowers, 
sometimes, it is true, suggested putrefac- 
tions, but quite as often went on almost in- 
sidiously and unobserved. Even after the 
first quarter of our century had gone by, 
slow decay was given a very large name, 
eremacausis, but yet was only imperfectly 
understood. The current explanation, such 
as it was, was in harmony with the few 
facts established by chemistry, viz., a 
theory of oxidation probably produced by 
the aggressive energy of freeoxygen. Iron 
rusted readily enough; why should not 
wood and teeth and fruits ‘rust’ also in 
a somewhat different, but still essentially 
similar, way. This hypothesis seemed to 
be confirmed by the fact that canned fruits 
and foods were preserved so long as air was 
excluded from them, but spoiled soon after 
being exposed to the atmosphere. It was 
not observed, or if observed it was for- 
gotten or believed to be immaterial, that 
meat and fish and fruits could be equally 
well preserved for an indefinite length of 
time by simple drying, although remaining 
constantly exposed in the dry condition to 
SCIENCE. 
123 
the aggressive action of the free oxygen of 
the air. 
Nitrification, or the conversion of nitrog- 
enous organic matter into mineral nitrates, 
was well known in the early part of our cen- 
tury as one of the most fundamental processes 
in nature and of prime importance in agri- 
culture; manures, for example, being nitri- 
fied before they could become fit food for 
green plants. Precisely how this nitrifica- 
tion was effected, however, was not known, 
although it was suggested that free oxygen 
somehow oxidized organic nitrogen by a 
process similar to that in which it attacks 
iron. Obviously, this process went on best, 
if not exclusively, in the soil, for organic 
nitrogen elsewhere showed little or no ten- 
dency to unite with oxygen to form nitrates. 
The soil seemed to have some peculiar prop- 
erty of favoring this oxidation, but exactly 
what this property could be, unless it were 
a kind of platinum-sponge effect, was by 
no means clear even to the most eminent 
chemists and naturalists. 
Natural ‘heating’ and ‘ sweating’ were proc- 
esses familiar enough to all observers of 
natural phenomena, but exactly what they 
meant no one in the early part of our cen- 
tury knew. Hay, imperfectly cured, heated 
and even rotted in the barn. Manure, col- 
lected in heaps, underwent a spontaneous 
and peculiar change by which it was altered 
or ripened, sometimes becoming intensely 
hot and giving off vapors which indicated 
profound and important chemical changes. 
Flax, in the course of the preparation of 
linen fiber, was made to undergo a peculiar 
maceration or change which must have sug- 
gested fermentation or decay and was known 
as rotting or ‘retting.’ Hides, in the pecul- 
iar and primitive processes preliminary to 
tanning, often underwent a similar change 
known as ‘drenching.’ Tobacco ‘sweated,’ 
and milk ‘soured,’ spontaneously. Cider 
‘turned ’ into vinegar, grape-juice into wine, 
and in various other domestic or indus- 
