ERYSIPELAS 187 



particularly if the agar is moist. When grown in broth the 

 virulence is rapidly reduced, but may be restored by passing 

 through an animal. In stab or shake culture in gelatine, 

 the colonies appear as small whitish spheres, but the 

 gelatine is never liquefied. Sternberg finds the thermal 

 death-point of the organism to lie between 52° and 54° C. 



Occurrence and Distribution. — The disease is less frequent 

 in the tropics than in temperate latitudes, and is found in 

 cold climates, such as Iceland and Greenland. The greatest 

 number of deaths in this country occurs in the months 

 of November and January, and the least in the summer 

 months. 



Women are more susceptible than men, but the mortality 

 among them is less, while it is very high in children up to 

 the first year of life. Traumatic erysipelas is most common, 

 and probably the cases that are termed ' idiopathic ' are 

 really due to a slight traumatic injury or abrasion so small 

 as to escape notice. This streptococcus is probably the 

 most frequent cause of puerperal fever. Predisposing 

 causes are wounds, injuries, overcrowding in surgical cases, 

 intemperance, want of proper nourishment, unhealthy and 

 dirty surroundings, and bad ventilation. The disease some- 

 times becomes endemic in a ward, and is expelled with 

 difficulty. It appears at times to exhibit very much more 

 marked powers of infectivity ; it is probably conveyed by 

 air as well, as by contagion and by fomites. Artificial im- 

 munity has been produced in rabbits, but the period of 

 protection is short ; when unprotected, the disease is fatal 

 to them in about half the number of cases. 



Dr. Bokenham is inclined to the opinion that the Strepto- 

 coccus erysipelatis and the Streptococcus pyogenes are the 

 same organism under different conditions. He has also 

 studied the Streptococcus pyogenes with a view of preparing 

 antistreptococcic serum, and considers it probable that a 



