8 
which, it is like an old Lion having lost its teeth and claws lying down 
between two young and powerful cubs. The relationship between them is 
clear and distinct but the older member seems nearly pushed out of 
existence by some unknown cause and it will probably soon disappear. 
With regard to Measles, a very old member of the family, systematic 
writers on medicines considered it as a form of Scarlet Fever to a period 
as late as 1793, and the diagnosis was not made until the issue of the second 
edition of Dr. "Withering' s Essay on Scarlet Fever, in that year. Others 
considered it as a mere form of Small Pox. This is sufficient to prove a 
family likeness. A further argument which I would advance in favour of 
my views is the fact that years which (through some not understood 
conditions) are favourable to the spread of one member of the family, are 
also similarly favourable to the others, It is a well-known fact that 
epidemics of Small Pox and Measles prevail generally at the same time, 
or the one follows in the wake of the other at a very short interval. 
Many other points might be mentioned to show that they are related to 
one another in their pre-historic origin. 
An objection might be made to my views that I have taken for granted 
that these diseases are the result of organic entities more or less 
permanent in their character during historic times. In answer to this I 
can only say that all sound tradition and written history tend to this 
conclusion. What Small Pox was in the Chinese and the Hindoo a 
thousand years before the Christian Era it is in the Cockney of to-day. 
What Scarlet Fever was in the time of the great and accurate observer 
Sydenham it is in our day.* There is not a particle of evidence on record 
which will logically tend to the conclusion that these Zymotic Diseases 
ever arise from any concatenation of conditions, f 
They have as strong a claim to be considered special creations as man 
himself, but on this I do not propose to speculate. When and in what 
* Where a Zymotic Disease has ever broken out in a new country it 
has been always traceable to communication from without. For instance, 
Scarlet Fever, Measles, Small Pox, &e., among newly discovered races, 
were always traced to the invader. Pulmonary Consumption also was 
unknown among the South Sea Islanders and the American Red Indians, 
until the arrival of Europeans. Is it not Zymotic ? Evidence points that 
way. 
f Every variety and mixture of filth was found among the Red Indians 
and South Sea Islanders, yet these never gave birth to any Zymotic 
Disease known to Europeans. The Pythogenic theory of Fevers, coupled 
with mere Sanitarianism, have retarded preventive medicine long enough. 
Dirt is not nice, but, like a certain personage, it may be painted too black. 
