372 
ANALYSIS OF CONTINENTAL JOURNALS. 
which does not possess the veritable attributes, we expose our¬ 
selves to the danger of falsifying the general theory that we wish 
to establish. To avert this serious inconvenience should be 
our first care; and to do so we will even risk the danger of 
falling into the inconvenient opposite: that is to say, we will 
erase from our outline, perhaps, maladies that are really viru¬ 
lent. This is altogether indifferent so far as the value of our 
systematisation is concerned. If the latter is established from 
the analytical documents exclusively furnished by the truly 
virulent maladies; if a rigorous logic has presided at the join¬ 
ing together and at the generalisation of the facts which have 
to be harmonised, and has united them in a homogeneous 
theory, this will remain intact when we shall at a later period 
be able to bring in new facts pertaining to maladies provision¬ 
ally excluded from the domain of virulency. What ought we 
then to understand by a virulent malady ? If it sufficed to 
answer this by giving examples, we would say smallpox, cow- 
pox, glanders, syphilis, rabies, &c. No one would then con¬ 
tradict us, and we could be understood by every one. Yes, the 
maladies we have just mentioned are very virulent. But it 
is necessary to say why; it is necessary to give them a short 
-and substantial definition—a definition which will neither 
tend to confuse nor be equivocal. But you will see that this 
definition cannot be formulated without introducing an ele¬ 
ment which will appear to you a gross begging of principles. 
In grounding the definition of virulent maladies on their 
fundamental character, that is to say, their transmissibility, 
one cannot define them otherwise than contagious maladies 
considered in a general manner. But all the contagious 
maladies are not virulent. 
The contagious diseases form a family, and the virulent 
maladies a genus in this family. It then becomes necessary 
to add to the definition of the latter a special character 
which, joined to the general character of transmissibility, 
enables us to distinguish this from the others, i . e. contagious 
diseases. But the only distinctive character that I can give 
you is hotly contested even now, and the proof of its reality 
constitutes precisely one of the principal objects of the study 
we are now undertaking. 
A few illustrations will make you better comprehend the 
difficulty which we are called upon to confront. It is not 
very long since the question which we are now examining 
appeared quite clear to every one. There were designated by 
the general name of ee contagious diseases” all the maladies 
capable of transmission from sick to healthy people ; and ac¬ 
cording as the transmission had for an agent a parasite or a 
