PERSISTENCE OF PUTREFACTIVE AND INFECTIVE ORGANISMS. 
203 
Not one of these bulbs has proved fruitful. They are all as brilliant and as free 
from life as they were after they had passed through the filter. 
The difference here indicated is worthy of notice. In the one case five minutes’ action 
completely sterilizes ; in the other ten minutes’ action fails to do so. This latter interval 
indeed might be multiplied twentyfold and still prove ineffectual. In the one case the 
process of boiling purged the liquid of its air ; in the other case the air was retained within 
and above the liquid. The case therefore connects itself with our former illustrations. 
On the 21st of February six bulbs were charged with fresh urine carefully neutralized 
and boiled for five minutes in an oil-bath. Of the six flasks, four remain perfectly clear 
and brilliant, one is slightly cloudy, and one turbid. 
The urine here referred to was neutralized in our own laboratory ; but as the 
importance of accurate neutralization has been much insisted on, I wished to check 
myself. At my request, therefore, Dr, Debus was good enough to send me from 
Greenwich a quantity of urine carefully neutralized by him. On the 1st of March 
seven retort-flasks were charged with the neutralized liquid. These were boiled for 
five minutes in an oil-bath and sealed during ebullition. Three of these flasks have 
become turbid, but four remain perfectly clear. 
On the 5th of March Dr. Williamson was good enough to send me a supply of 
neutralized urine collected in a public urinal in University College. The colour was 
very deep, the odour was very bad, and the precipitation on boiling very copious. 
Fourteen retort-flasks were charged with this liquid on the 6th of March. Seven of 
them have gone bad, but seven of them remain clear. 
On the 10 th of March Dr. Fkankland was good enough to send me a supply of 
urine neutralized by himself. It was introduced into four retort-flasks, which, like the 
others, were boiled for five minutes in hot oil and sealed during ebullition. None of 
these flasks have shown the slightest sign of yielding. The liquid within all of them 
is as brilliant as it was when first introduced. 
In every case here mentioned the liquid, after boiling, was exposed for several days 
to a temperature of 50° C. 
The conflict described in the foregoing pages and the search for principles to reconcile 
the results occupied me too long to permit of my doing more than break ground on the 
subject of urine. I entertain, however, a strong opinion that by a little practice with 
this liquid, its sterilization by five minutes’ boiling might be rendered certain in every 
case. As the experiments stand, they sufficiently negative the conclusions of Dr. Bastian, 
who has brought forward the deportment of neutralized urine as a specially convincing 
illustration of spontaneous generation. Nor are they in accordance with the statement of 
M. Pasteur, that in neutralized urine, subjected only to the ordinary boiling temperature, 
organisms in the majority of cases (“ le plus souvent”) appear. 
§ 28. Hermetically sealed flasks exposed to the sun of the Alps . 
A remark of Dr. Bastian’s, wherein he refers to the power of the actinic rays of the 
