54 
PROFESSOR TYNDALL ON THE OPTICAL DEPORTMENT OF THE 
the fluids have been so much degraded in quality by exposure to the temperature of 
212° Fahr., and have thereby, in all probability, been rendered far less prone to engender 
independent living units than the unheated fluids in the tissues would be” *. 
We have here, to use the words of Dr. Bastian, “ a question lying at the root of the 
pathology of the most important and most fatal class of diseases to which the human 
race is liable.” Let us now examine his settlement of the question, as described in 
the foregoing extract by himself. 
§ 22. Experiments with Hermetically sealed Vessels. 
Experiments with hermetically sealed tubes were begun on the 5th of October. The 
shape of the tubes after sealing is represented in fig. 8. Each of them 
contained about an ounce of liquid. They were boiled for only three 
minutes in an oil-bath, and were sealed, during ebullition, not by a 
blowpipe, but by the far more effectual spirit-lamp flame. 
Hay . — Four tubes were charged on the date mentioned with a 
strong infusion, four with a weak infusion. All eight flasks remain 
to the present hour clear. 
Turnip . — Two kinds of turnip were tried in these first experiments. 
Two tubes were charged with a strong infusion, and two with a weak infusion of a 
sound hard turnip ; while two other pairs of tubes were filled with strong and weak 
infusions from a soft woolly turnip. All the tubes remain transparent to the present 
time. Two or three days’ exposure to the air of the laboratory sufficed to cloud all these 
infusions and fill them with life. 
On the 8th of October twenty-one tubes were charged with infusions of the following 
substances : — Mackerel, beef, eel, oyster, oatmeal, malt, potato. There were three tubes 
of each infusion. All of them remain to the present hour unchanged. 
I had not previously seen a more beautiful illustration of the dichroitic action which 
produces the colours of the sky than in the case of the oyster-infusion. With reflected light 
it presented a beautiful cerulean hue, while it was yellow by transmitted light. This 
was due to the action of suspended particles which defied the power alike of ordinary 
filtration and of the microscope. At right angles to a transmitted beam the infusion 
copiously discharged perfectly polarized light. Suspended particles in the potato- 
infusion produced a somewhat similar effect, but it was by no means so fine as that of 
the oyster-infusion. By ordinary filtration it was not possible completely to rid the malt 
and oatmeal of suspended matter ; but both remain] exactly as they were when the 
flasks containing them were sealed. 
These experiments had been made before the volume of the Transactions of the Patho- 
logical Society containing the discussion referred to above came into my handsf. 
* Transactions of the Pathological Society of London, 1875, p. 272. 
t To the courtesy of Dr. Bastian I am indebted for a separate copy of the report of the discussion here 
referred to. 
Fig. 8. 
