DE. W. EOBEETS ON BIOGENESIS. 
469 
at a, and pushed the narrow point («) into the duct of the teat. Holding it firmly in 
this position, I milked into the test-tube until sufficient milk had been obtained. I then 
drew the test-tube away from the little tube, pressing in the cotton-wool 
around it as I did so, until the latter was entirely withdrawn from the 
test-tube. Operating in this way I trusted to obtain milk, if not 
entirely free from extraneous germs, at least containing but few of 
them. 
From a test-tube thus filled I charged ten empty sterilized tubes in 
the manner already described, and resealed their capillary orifices. Of 
these ten, three remained unchanged. When examined from three to 
six weeks afterwards the milk in them was perfectly sweet to the taste, 
its reaction was neutral or faintly acid, like that of fresh milk, there 
was no curdling, and no signs of organisms under the microscope. The 
other seven changed within ten or twelve days. Some of them curdled 
and others putrefied; all became highly acid, and, under the microscope, 
Bacteria , either staff-shaped or spherical, were found in them. 
6. Grape-juice . — Eleven sterilized tubes, six empty and five containing 
water, were charged with grape-juice in the following manner : — A fresh 
grape was firmly seized with the fingers and thumb, and a spot on its 
surface was pressed for a few seconds against the flame of a spirit-lamp 
so as to destroy any adhering germs. The point of the sterilized tube, -^bout half the 
• in i-ii --irfi actual size, 
also heated tor a moment m the flame, and quickly snipped off by an 
assistant, was then thrust into the grape at the heated spot. Compression was now 
made on the grape until a sufficient quantity of the turbid juice was forced into the 
tube. The tube was then withdrawn and its point sealed in the flame. The eleven 
tubes thus charged remained permanently unchanged. When examined at various 
periods, from five to eight weeks, they were all found free from organisms, and the 
taste and reaction of their contents were indistinguishable from those of the fresh 
grape-juice. 
7. Orangejuice . — Eight sterilized tubes, four empty and four containing water, 
were charged with orange-juice. The oranges were fresh from the trees*. A portion 
of the rind was stripped off, and the capillary end of one of the tubes, momentarily 
heated in the flame, was snipped off and thrust into the orange. The orange was then 
compressed until a sufficiency of the juice was squeezed into the tube, which was then 
withdrawn and sealed in the flame. The tubes thus charged were examined at various 
intervals, from four to eight weeks ; all were found perfectly free from organisms, and 
preserved unaltered the reaction and taste of fresh orange-juice. 
8. Tomato juice . — Three sterilized tubes, containing water, were charged with the 
* This and all the other experiments in this section, except the first set with egg-albumen, were performed 
at San Eemo during November, December, and January, 1873-74. 
Eig. 4. 
