560 A MANUAL OF BACTERIOLOGY 



of acute dysentery in the United States, conclude that the disease, 

 whether sporadic, " institutional," or epidemic, is due to the B. 

 dy sentence of Shiga. 



The B. dysenterice (Shiga type) has been isolated by Eyre, 

 McWeeney, and others from cases of ulcerative colitis or asylums 

 dysentery in the British Isles (see pp. 376-379). 



The Balantidium coli (p. 507) and certain parasitic worms may 

 also induce a dysenteric condition. 



SKIN DISEASES : Acne. In the acne pustules, the M. pyogenes 

 var. aureus, with or without var. albus, is almost invariably present, 

 and a staphylococcic vaccine generally acts extremely well. In 

 the comedoes a Gram-positive, Hofmann-like bacillus (B. acnes) 

 is present in considerable numbers, and may be the cause of the 

 comedo. This organism was cultivated by Fleming on a neutral 

 agar to which glycerin and oleic acid are added. Siidmersen and 

 Thompson * cultivate it on an acid ( + 40) serum-agar. The organism 

 is anaerobic, at least at first, and will grow in glucose-agar stabs. 

 In culture the organism is diphtheroid. A vaccine prepared with 

 it is of service in the comedo stage. 



Eczema is produced by the action of the pyogenic cocci (M. 

 pyogenes, var. aureus and albus). Virulent cultures of these organ- 

 isms, with or freed from their toxins, seem, however, to produce 

 an impetigo rather than eczema. But the filtered cultures, i.e. 

 toxins, are harmful to the skin, and when applied to it for one or 

 two days by means of moist warm pads a typical papular or vesi- 

 cular eczema ensues. Probably in the human subject in addition 

 to the micro-organisms some peculiarity in the soil is necessary 

 for the disease to develop. 2 In so-called seborrhceic eczema, a 

 non-liquefying micrococcus which forms butyric acid has been 

 isolated. 



Impetigo. The large vesiculo-bullous eruption of impetigo con- 

 tagiosa is caused by the Streptococcus pyogenes ; the small pustule 

 in the neighbourhood of hair-follicles, impetigo of Bockhart, is 

 caused by the M. pyogenes var. aureus. The B. diphtheria may 

 also cause an impetigo (p. 273). 



Pemphigus. A diplococcus has been isolated in acute pemphigus 

 by Demme, and in the chronic form by Dahnhardt. Bulloch and 

 Russell Wells, in this country, seem to have isolated an identical 

 organism, and the following description of it is taken from their 

 papers. Cocci 0-8 to 1-5 p in diameter, mostly arranged as diplo- 

 cocci, and staining by Gram's method. On surface agar the organ- 



1 Journ. of Pathol. and Bacterial., vol. xiv, 1910, p. 224. 



2 Whitfield, Practitioner, February 1904, p. 202. 



