198 
Dll. L. WALDSTEIN. 
put into two test tubes, into one of which a stream of air charged 
with ammonia was led, until the alkaline litmus reaction \vas 
obtained, the other remaining intact. Both were then closed by 
means of a cotton plug and examined after forty clays. The 
contents of the second tube w^ere in appearance and reaction un- 
changed, whereas the first was turbid and contained much 
zoogloea, and literally swarmed with different forms of organisms. 
It is worth noting that litmus paper indicated neutral reaction, 
but rosolic acid solution gave a very strong alkaline reaction. 
A review of the above^-described experiments shows, as regards 
Dr. Bastian’s work, that in urine and the modified Mayer^s solution 
containing urea, micro-organisms are developed or multiply after 
exposure to 212° B. (100° C.) for a certain length of time, after 
evacuating the greater part of oxygen and placing the retorts in 
an incubating temperature 122° F. (40 — 45° C.). But in the 
series here recorded this effect was produced only after a com- 
paratively long time. It has also been found that it is not safe 
to draw conclusions regarding the presence of organisms in fluids 
from their outward appearance, i. e. the clearness or turbidty of the 
same, as the suspensions and sediments are frequently composed of 
other bodies, and as perfectly clear fluids often contain numberless 
organisms. Dr. Bastian found that micro-organisms appeared 
alone in such of the retorts as held urine mixed with liquor potassae, 
and that after eighteen to thirty- six hours, w hilst the urine un- 
mixed invariably remained apparently unaltered. My repetitions 
of his experiments have led to a different result ; in all specimens, 
irrespective of the admixture of liq. pot.. Bacteria were developed, 
but only after a much longer sojourn in the incubator. The 
fact that they appeared sooner w'here the alkali had been added 
is explained without difficulty by the accelerated decomposition 
of urea and generation of ammonia, which provided the necessary 
nitrogen ; in so far, it is true, liquor potassse acts as a favorable 
factor. 
As long as a doubt can be entertained regarding a per- 
fect sterilisation, so long is it inadmissible to make use of these 
results as arguments in favour of abiogenesis.” I am inclined 
to consider these researches of some interest, inasmuch as the re- 
tardation of a development of low^r forms or so-called germs 
w'hich may have remained in the vessels can be naturally ex- 
plained by the high temperatures and exclusion of free oxygen, 
wdiilst the multiplication of organisms can be understood w^hen the 
incubator temperature and the generation of a simple nitro- 
genous body are considered as favorable factors. Urea may not, 
according to Cohn, be such a body, but when ammonia is gene- 
rated in presence of the necessary inorganic substances Bacteria 
can multiply even without an unlimited supply of free oxygen. 
