Is not this the way that infective diseases have appeared on the earth from age to age?

It was no new thing to say, or to guess, that phthisis was or might be infective.

As with typhoid, so with Malta fever, cholera, and some other infective diseases.

But morbus pauperum is not the only principle of infective disease.

Nor does the blood imbibed by the flea cease to be infective when it passes from the stomach.

The resting stage was infective while the active stage was not.

In a few cases the larv from an infected female were infective.

Hitherto the advances in knowledge upon the etiology of other infective diseases have done little toward the etiology of cholera.

This part of their habitat should thus be contaminated with infective stages of both parasites.

The progeny of lice which have fed on infected blood may themselves be infective.