December 3, 1870.] THE PHARMACEUTICAL JOURNAL AND TRANSACTIONS. 
453 
and the immunity from recurrence of such diseases as 
scarlet fever and small-pox. 
The physical theory differs from the vital in that it 
places the reproductive force of the virus in the animal 
itself. It does not dispute that the poisons assume the 
solid form, and are carried about by water and air, but 
it declares their perfect destructibility. The result of 
experiments by Fordyce, confirmed by Chauveau,—show¬ 
ing that the virus of small-pox, diluted by water up to a 
certain point, is active, but beyond that point inert, — 
was explained by the germ-theorists as being caused by 
the mechanical distribution of the germs by the water, 
which lessened the certainty of inoculation. The physi¬ 
cal theorists, besides this, assume the molecular disinte¬ 
gration of the particles by water. The author had found 
that, after diluting snake poison largely with water, not 
only was its power to infect destroyed, but evaporation 
of the water and reconcentration failed to bring it back. 
Dr. Richardson looks upon the poisons as organic pro¬ 
ducts, particles derived from the secretions of the animal 
body. Thus, a person suffering from a communicable 
disease is poisonous precisely as a cobra di capello is poi¬ 
sonous,—that is to say, he produces by secretion an 
organic poison which, coming in contact in the right 
way with a healthy person, produces disease. In some 
cases, a change in the natural secretion is induced by 
direct contact with the poisonous matter, causing it, as it 
is poured out, to be changed into a substance the same as 
that which excited the action; this may either be car¬ 
ried away and replaced by a new and healthy secretion, 
in which case there is recovery, or be absorbed into the 
blood, exciting change there also, and so lead to disor¬ 
ganization of the blood and death. In other cases, the 
secretions themselves undergo decomposition, arising 
from atmospheric influences, or the constitutional ten¬ 
dencies of the person affected, the effects following being 
precisely the same as those following its introduction 
into the body. The author also maintained that the 
physical theory explains the specific character of each 
poison. Whatever the mode of entrance of the poison, 
it acted according to its nature, by making election of one 
particular secretion. It also explains the limitation of 
the poisons, for, if it be the particles of an animal secre¬ 
tion that become poisonous, their production and dis¬ 
semination must cease with the life of the animal. This 
is the fact; the dead are not contagious like the living, 
and epidemics cease as their poisons are resolved into 
elementary forms of matter. He claimed also that it 
accords with the facts relating to the seasons, it being 
natural that changes in secreted fluids should be most 
active when there is excess of moisture in the air and 
coldness. 
Dr. Richardson said that if the evidence of such change 
was insufficient, it was better than any produced for the 
germ theory. In the study of change of colloidal bodies 
by contact, the action of the different oxygens on animal 
fluids, the action of known organic chemical compounds 
such as nitrite of amyl, there was ample suggestion for 
experimental research on the organic poisons derived 
from animal bodies. In conclusion, his object had been 
to show that the germ theory of the origin of communi¬ 
cable disease was not to be accepted in one eager grasp 
as the absolute truth; that, beautiful as it was from 
analogy, and grand as it was as a generalization if it 
were true, it might after all be a delusion. 
SOCIETY OF ARTS. 
Ox Fermentation. 
BY TROFESSOR A. W. WILLIAMSON, F.R.S. 
Lecture III. — continued. 
I stated that exposure to a red heat was found by 
Pasteur to act effectually in destroying the vitality of 
these little particles, and in every case in which he used 
air which had been subjected to that heat, he found that 
the air was incapable of sowing any of these organisms 
in liquids even the most favourable to them. There was, 
however, still one remarkable exception, which was pre¬ 
sented by the experiment of Gay-Lussac, to which I 
alluded some time ago. He found that when he used a 
mercury trough, which he selected as giving him the 
best condition for the purpose, he got these little cells 
produced from the air which had been calcined. Now, 
Pasteur found that mercury exposed to the air, as it 
is in these operations, has adhering to it a number of 
these little germs, and that when no more than the 
ordinary precautions are taken for cleansing the mercury, 
it has with it a considerable variety of such little or¬ 
ganisms, which, if placed in a suitable material, develop 
themselves and grow quite well. He proved this in 
various ways. For instance, some of the little bulbs 
which had been sealed up whilst full of fermentable 
liquor and steam, and which had been kept for some time 
in a warm chamber, so as to bo certainly free from vital 
organisms, were opened under mercury, so as to allow 
the ends of the tubes to be filled with mercury. He 
then lifted it up, so that nothing came into contact with 
the liquid but mercury, and passed into them sometimes 
air which had been passed through a red-hot platinum 
tube, and sometimes oxygen gas given off from molten 
chlorate, where certainly there would be nothing of or¬ 
ganic life present, and in almost all these cases he found 
that organisms developed themselves. He attributed 
this entirely to the mercury, because when that was ab¬ 
sent the result was the opposite. In order to prove this 
point more decisively, he took a liquid which was cap¬ 
able of decomposing, kept it for some time in a quiescent 
state, and then allowed a drop of mercury, in the state 
in which he had been using it before, to flow into it, and 
put the mixture into his warm chamber. He soon found 
that the mercury had carried in the germs of these 
organisms, and that they developed themselves quite well 
in it. Certainly any one unaccustomed to such accurate 
precautions could hardly have anticipated such a result 
as that, and a result which is, I think, most instructive,, 
as showing what extraordinary precautions are needed, 
in order to prevent the entrance of these excessively 
small particles into the materials which we are working 
with. Side by side with this, I must mention another 
result of Pasteur’s, for it was, perhaps, hardly less start¬ 
ling, and that was, that when, instead of taking the 
liquid which I mentioned to you just now, yeast-water 
and sugar, he took common cow’s milk, or, at all events, 
the mixture which is sold by that name, and boiled it, 
with a view of destroying any organisms that might be 
in it, and then he sealed up the bulb while still full of 
steam, so that no air could get into it, and when he kept 
such sealed-up bulbs for some time in a warm chamber, 
he found clear evidences of decomposition; he found a 
turbidity in the substance, a curdling of the nitrogenized 
materials of the milk : and on taking out som e ot it, ho 
found it was swarming with little animalcula ; and yet 
he had boiled the milk for a considerable time, and had 
closed the vessel whilst the ebullition was still going on, 
so that no air could have carried the germs into it before 
it was closed. Still, there were the little organisms unmis¬ 
takably present. He then modified his experiment in 
this manner. He boiled his milk at a higher temperature. 
I need hardly tell you how that can be done. You are, 
of course, aware that the temperatures at which water, 
or milk, or any liquid boils arc different, according to 
the pressure which the air exerts upon it; that is to say, 
if you were to boil water here, and then if you were to 
carry it to the top of St. Paul’s, and notice the tempe¬ 
rature in each case, you would find that at the greater 
height it would boil at a lower temperature. If, in like 
manner, you carried it down to the bottom of a deep 
mine, and boiled it there, you would find the tempe¬ 
rature would be higher; the greater the pressure ot tho 
superincumbent air, tho higher the temperature at which 
any liquid boils. Pasteur wanted to make his milk boil 
