ATMOSPHEEE IN RELATION TO PUTREFACTION AND INFECTION. 
41 
that the water of condensation trickled from a chink in the bottom. The other cases were 
mended as far as possible, and into them the infusions were introduced on the 4th of 
January. Each case, as before, was provided with three exposed tubes for comparison with 
the three protected tubes within. On the morning of the 6th the exposed turbot-infusion 
■was clear in all the tubes; a few hours subsequently two out of the three became 
cloudy ; while on the 7th Bacteria had taken possession of all of them. All the unpro- 
tected tubes of codfish were cloudy on the 6th, more cloudy on the 7th, and covered 
with a soapy layer upon the 8th. The three exposed herring-tubes were also cloudy on 
the 6th, the cloudiness advancing afterwards to thicker turbidity. The mullet gave way 
in the same manner. For more than three months the protected tubes, including even the 
imperfect chamber which protected the mullet-infusion, have remained as clear as they 
were upon the day of their introduction. 
To these fish-infusions may be added others of eel and oyster. Two tubes of each, 
protected by lamp-glasses, were charged on the 27th of December. They remain 
unchanged. Two other pairs of tubes, prepared in the same way and exposed to the 
laboratory air, are turbid and covered with Penicillium. 
13. Infusions of Fowl and Kidney. 
Three tubes of the fowl-infusion were introduced into a case, and boiled there for five 
minutes, on the 4th of January. Three similar tubes were at the same time exposed to 
the air. On the 6th all the outer tubes were cloudy, the cloudiness becoming denser 
on the following days, while disks of Penicillium began to form on the exposed sur- 
faces. It was found exceedingly difficult to obtain a clear infusion of kidney. The 
liquid, after it had passed through a dozen filters, was still quite muddy. With con- 
siderable labour and care, and by the employment of 200 filters, the mechanically sus- 
pended matter was at length removed, and a hyaline infusion obtained. It was introduced 
into its case, to which three exposed tubes were attached, on the 4th of January. On 
the 7 th the latter were perceptibly cloudy, on the 8th distinctly so, while specks of 
mould rested upon them all. The protected tubes, on the contrary, have for months 
maintained their transparency undimmed*. 
The entire number of experiments made to illustrate the association of scattered 
light and Bacterial and fungoid life are not here recounted. Whiting, for example, may 
be added to the fish, and pork to the flesh examined, while many of the other substances 
have been tested oftener than I have thought it necessary to record. The method of 
boiling was also varied in a manner which may claim a passing reference here. 
§ 14. Boiling by an Internal Source of Heat. 
Two large test-tubes were fixed air-tight in the same case. On the 8th of November, 
* Kidney has been mentioned by Dr. Bastian as a substance with which he demonstrates the occurrence of 
spontaneous generation. He does not mention the extraordinary turbidity of the infusion, which proved so 
troublesome to me. 
