SUPPURATION. 151 



and we have seated deeply in our derm a coccus which 

 can at times cause abscess-formation, the conclusions of 

 Robb and Ghriskey, that sutures of catgut when tightly 

 drawn may be a cause of skin-abscesses by predisposing 

 to the development of this organism, are certainly justi- 

 fiable. 



Not only does the coccus occur in the attenuated form 

 described, but we have very commonly present upon the 

 skin, generally as a harmless saprophyte, the important 

 Staphylococcus pyogenes albus, which is a common cause 

 of suppuration. 



Although, as stated, the Staphylococcus pyogenes albus 

 is a common cause of suppuration, it rarely occurs alone, 

 the studies of Passet showing that in but 4 out of 33 cases 

 which he investigated was this coccus found by itself. 

 When pure cultures of the coccus are injected subcu- 

 taneously into rabbits and guinea-pigs, abscesses some- 

 times result ; sometimes there is no result. Injected 

 into the circulation of these animals, the staphylococci 

 sometimes cause septicemia, and after death can be found 



FIG. 44. Staphylococcus pyogenes aureus, from an agar-agar culture; x 1000 



(Gunther). 



in the capillaries, especially of the kidneys. From these 

 illustrations it will be seen that the organism is feebly 

 pathogenic. 



