ORGANISMS OF SKIN 695 



The S. pyogenes and M. pyogenes, var. aureus, alb us, and citreus, 

 and the M. epidermidis (albus) of Welch, are the commonest (see 

 p. 274). Equally common on the skin and scalp is the scurf micro- 

 coccus isolated by Gordon (see table, p. 274). Sarcinae, bacilli, 

 and moulds occur also. On the skin of the groin, scrotum, and 

 vulva the smegma bacillus occurs. From sweating feet various 

 organisms have been isolated, which on culture evolve a dis- 

 agreeable odour, among which is the Bacterium fetidum of Thin. 



Conjunctive. Some observers have stated that the conjunctiva 

 is generally sterile. A certain number of organisms are, however, 

 usually present, though they are not numerous, the commonest 

 species being the Micrococcus epidermidis (albus) of Welch, and 

 if artificially inoculated the excess is rapidly eliminated. The 

 B. xerosis can often be isolated. 



Lawson 1 found the normal conjunctiva to be sterile in 20 per 

 cent, of cases and pyogenic cocci to be rare, and, when present, 

 non-virulent. 



Nose. In the anterior nares crusts and vibrissse micro- 

 organisms are present in great abundance, but, contrary to the 

 usual opinion, St. Clair Thomson and the Author 2 showed that 

 the mucous membrane of the interior of the nose is comparatively 

 sterile, and when organisms are present they are very scanty 

 compared with the number of organisms inspired. Moreover, 

 organisms artificially deposited were found to be rapidly disposed 

 of. After two hours, for example, B. prodigiosus inoculated on to 

 the inferior turbinate could not be detected by cultivation. 

 Wurtz and Lermoyez asserted that the nasal mucus is germicidal, 

 but St. Clair Thomson arid the Author 3 were unable to confirm 

 this, though it may have an inhibitory action. 



Air-passages. Below the larynx under normal conditions the 

 air-passages are free from micro-organisms. Expired air is also 

 free from organisms, and the air from the naso -pharynx after 

 passing through the nasal cavities is deprived of the majority 

 of its organisms. 4 



1 Trans. Jenner Inst. Prev. Med., vol. ii, p. 56 ; also Griffith, Thompson 

 Yates Lab. Rep., vol. iv, pt. i, 1901, p. 99. 



2 Medico-Chirurg. Trans., vol. Ixxviii, 1895 (Bibliog.). 



3 " The Fate of Micro-organisms in Inspired Air," Lancet, 1896, 

 January 11. 



* Ibid. 



