virulency

The fever, though it was October, had scarcely abated; indeed, on the contrary, it seemed to have revived and increased in virulency in consequence of the premature return of many people who had fled on its first appearance, and who in coming back too soon to the infected atmosphere, were less able to withstand contagion than those who had remained.

The Hidden Hand 1888

But that thou mightest, reader, both know, and with equal indignation abhor, the snarlings and virulency of these men, take it in their own words, although I cannot without infinite reluctancy allege what they with all audaciousness have uttered.

From the Talmud and Hebraica 1602-1675 1979

The veterinarian is in no position to estimate the virulency of organisms so introduced; neither can he determine the exact degree of resistance possessed by the subject in any given case.

Lameness of the Horse Veterinary Practitioners' Series, No. 1 John Victor Lacroix

Experience teaches that the natural course and termination in these cases are modified by the location and depth of the injury, virulency of the contagium and resistance of the subject to such infection.

Lameness of the Horse Veterinary Practitioners' Series, No. 1 John Victor Lacroix

A sub-coronary abscess which, because of lack of proper care or because of virulency of the contagium or low vitality of the subject, is quite apt to result in cartilaginous affection and its perforation by necrosis follows.

Lameness of the Horse Veterinary Practitioners' Series, No. 1 John Victor Lacroix

The blood of the civilized race has become so thoroughly syphilized, that it is no longer so susceptible to the disease as it once was: and the disease as we know it to-day does not manifest the same virulency as it did years ago, or as it does in a race in whom it is grafted for the first time.

The Eugenic Marriage, Vol. 3 (of 4) A Personal Guide to the New Science of Better Living and Better Babies

These cultures, left alone without any possible external contamination, undergo, in the course of time, modifications of their virulency to a greater or less extent.

A History of Science: in Five Volumes. Volume IV: Modern Development of the Chemical and Biological Sciences 1904

Madame Mayer hated Corona d'Astrardente, Ugo del Ferice detested Giovanni with equal virulency, not only because he had been so terribly worsted by him in the duel his own vile conduct had made inevitable, but because

Saracinesca 1881

If the blood has received any hereditary taint, the lymphatic glands not only reproduce it but often increase the virulency of the original disease.

The People's Common Sense Medical Adviser in Plain English or, Medicine Simplified, 54th ed., One Million, Six Hundred and Fifty Thousand Ray Vaughn Pierce 1877

The fever, though it was October, had scarcely abated; indeed, on the contrary, it seemed to have revived and increased in virulency in consequence of the premature return of many people who had fled on its first appearance, and who in coming back too soon to the infected atmosphere, were less able to withstand contagion than those who remained.

Capitola's Peril A Sequel to 'The Hidden Hand' Emma Dorothy Eliza Nevitte Southworth 1859