ANALYSIS OF CONTINENTAL JOURNALS. 765 
and there, and as much more distant from each other as the 
dilution is increased. 
2. The substances dissolved in the serum, and withdrawn 
separately from the humours, are shown to be completely 
destitute of all virulent activity. 
3. The same isolation being practised on the definite par¬ 
ticles suspended in the serum, inoculation with them, when 
isolated in an absolute manner, produces the same effects as 
those resulting the entire humour. 
A.—Influence of the dilution of Virulent Humours on the 
manifestations of their activity . 
Everyone knows the celebrated experiments by which the 
illustrious physiologist, Spallanzani, demonstrated that the 
fecundating property of the semen does not reside in the 
elements of its fluid portion, but that the spermatozoa 
which move about in it in such prodigious quantity are 
the agents to which it owes its specific activity. Among 
these experiments is one which seemed to me likely to furnish 
the elements of a probable solution of the physical condition of 
the actual agents of virulent humours, and it is by this primary 
tentative that I will inaugurate my demonstrations. 
It is known that Spallanzani, being possessed of the idea 
of producing the artificial fecundation of fish ova with semen 
diluted in water, discovered : 1st, that the relatively w T eak 
dilutions acted like pure semen, all the ova sprinkled with 
the liquid becoming impregnated and developed ; 2nd, that 
with the dilutions carried to a high degree, only a certain 
number of ova were fecundated, although all were saturated 
in the same manner by the fecundating fluid. Such a result 
could only be explained by admitting that the fecundating 
property was the appanage of particles dispersed here and 
there in the fluid ; the ova which met them were impregnated, 
and those which did not remained sterile. If the activity of 
the semen resided in the substances in the liquid condition, 
in the matters dissolved in the water, all the liquid molecules 
would necessarily possess this activity to the same degree; so 
that in every case, with the w T eak as with the strong dilutions, 
or even with the pure semen,impregnation would be manifested 
in an equal manner. It is because it is not so that we determine 
to ascribe the fecundating faculty to the corpuscular elements 
of the spermatic humour. Evidently this is not a direct and 
peremptory demonstration ; but among the indirect proofs of 
the part played by the spermatozoa there is none more 
eloquent or significant. 
