PRODUCERS OF ABSCESSES. ( I.LLULIT1S AXD SEPT K. I- MI.\ 331 



vitality for a year or more. Suspended in water its thermal death point 

 varies with different cultures and averages about two hours at 50 C., one- 

 half to one hour at 60 C., ten minutes at 70 C., and five minutes at 

 80 C. Upon silk threads and in media rich in organic matter its 

 resistance is greater, but subjected to 80 C. for thirty minutes or boiling 

 for two minutes it is almost surely killed. Cold has but little effect. 

 Thirty per cent, of the organisms remained alive after being subjected 

 by us to freezing in liquid air for thirty minutes. 



They are quite resistant to direct sunlight and to drying. Dried pus 

 contains living staphylococci for weeks and even months, and they can 

 be found alive in the fine dust of the air in living and in operating rooms. 



EFFECT OF CHEMICALS. In water they remain alive for several weeks. 

 To most disinfectants the staphylococci are rather resistant. The 

 presence with staphylococci of organic substances, especially albumin, 

 increases their resistance. In watery solution dissolved mercuric 

 chloride, 1 : 1000, destroys the organisms in five to fifteen minutes, 

 but when in pus not for several hours. 



Hydrogen peroxide in 1 per cent, solution kills in about one-half hour. 

 Methyl alcohol in 50 per cent, solution kills staphylococci on silk threads 

 in ten minutes. The same effect is obtained by carbolic acid in 3 per 

 cent, solution or lysol in 1 per cent, solution. Formaldehyde in watery 

 solution acts only in concentrations of 5 per cent, or over. 



P thoren'sis. The pathogenic effect of the staphylococcus pyogenes 

 aureus on test animals varies considerably, according to the mode of 

 application and the virulence of the special culture employed. In the 

 experiments so far made this micrococcus, as found in suppurative 

 processes in the human subject, has not proved to be as infectious for 

 animals as it is for man. In man a simple rubbing of the surface of the 

 unbroken skin with pus from an acute abscess is, as a rule, sufficient 

 to produce purulent inflammation, and the introduction of a few germs 

 from a septic case into a wound may lead to a fatal pysemia. These 

 conditions can only be reproduced in lower animals with difficulty, and 

 by the inoculation of large quantities of the culture. Subcutaneous 

 injections, or the inoculation of open wounds in mice, guinea-pigs, and 

 rabbits, are commonly without result; occasionally abscess formation 

 may follow at the point of inoculation, which usually ends in recovery. 

 The pus-producing property of the organism is exhibited in proportion 

 to the virulence of the culture employed. Slightly virulent cultures, 

 which constitute the majority of those obtained from pus taken from 

 the human subject, when injected subcutaneously in large quantities 

 (several c.c. of a fresh bouillon culture) in rabbits or guinea-pigs, give 

 rise to local pathological lesions- -acute abscesses. When virulent 

 cultures are used which are rarely obtainable 0.5 c.c. of a fresh 

 bouillon culture is sufficient to produce similar results. The abscesses 

 generally heal without treatment; sometimes the animals die from 

 marasmus in consequence of the suppurative process. In intraperitoneal 

 inoculations the degree of virulence of the culture employed is still 

 more conspicuous in the effects produced. The animals usually die in 



