476 
DR. W. ROBERTS ON BIOGENESIS. 
peas were first finely crushed in a mortar. Both these flasks remained unchanged for 
a period of seven months; but in the beginning of June 1872 the contents of the first 
flask became turbid and covered with a film, and, when examined under the microscope, 
revealed abundance of short staff-shaped Bacteria. The reaction, originally neutral, 
was now faintly alkaline. The second flask remained apparently unchanged for sixteen 
months ; and when the contents were examined at the end of that time no trace of 
organisms could be found under the microscope, and the reaction was neutral. 
2. May 4, 1872. — Two plugged flasks, charged with very thin gruel, were gently 
boiled over the flame for fifteen minutes. These flasks remained apparently unaltered 
for six weeks, and then one of them began to exhibit rapid changes. Its contents 
became more diffluent and yellower and covered with a pellicle. On July the 13th this 
flask was opened for examination. Its contents were faintly acid (originally neutral), 
and had a smell of sour dough (all the starch had disappeared), and abundance of 
spherical Bacteria were seen with the microscope. The other flask, also opened for 
examination on the 13th of July, was quite unaltered. Its contents were neutral, 
odourless, reacted strongly with iodine, and contained no trace of living organisms. 
Kesults of this kind, standing alone, would not have produced much impression on 
my mind, because, although exceptional in some respects, they were of the same order 
as those witnessed in defective sterilization, the organisms discovered being of the 
same kind as those ordinarily produced by extraneous infection. They might there- 
fore have been regarded simply as faulty experiments*. 
But the two following results very strongly arrested my attention. Not only did 
organisms appear under exceptional conditions, but they were of a species distinctly 
different from the organisms with which I was so familiar as the result of extrane- 
ous infection. 
1. July 17, 1872. — A plugged bulb, charged with a highly albuminous urine, was 
boiled in a can of water for twenty minutes. When cold the neck of the bulb was 
filed off above the cotton-wool, and it was set aside in a warm place. An abundant 
precipitation of albumen had occurred, and the supernatant fluid was perfectly trans- 
parent. 
This remained unaltered until the beginning of March 1873, a period of nearly eight 
months. At this time I noticed the appearance of numerous whity-brown specks, like 
small pins’ heads, scattered on the sides of the glass at and near the surface of the 
fluid. To the naked eye they looked like specks of solidified fat, but with the aid of a 
lens they were seen to have a radiated structure. These specks steadily, though slowly, 
grew and multiplied, until at the end of six weeks some of them were as large as hemp- 
seeds. The supernatant fluid still continued perfectly transparent. On the 28th of 
April the bulb was opened for examination. The urine was, as at first, acid. Under the 
* It seemed possible that in some of these cases minute insects might have crept into the flasks or bulbs 
through the cotton-wool plugs, and thus communicated infection to their contents. 
