122 VACCINE AND SERUM THERAPY. 



ANTI-DYSENTERIC SERUM. 



Soon after the discovery of the bacillus of dysentery by 

 Shiga in 1892, the treatment of bacillary dysentery by the use of 

 immune sera was undertaken. It was found by Shiga, that the 

 organism which is now regarded as the etiological factor in bacillary 

 dysentery is readily agglutinated with blood from patients suffer- 

 ing with this disease. Following the discovery of the etiological 

 importance of this organism in the dysenteries in Japan this or- 

 ganism was found by Flexner in the dysenteries in the Philippine 

 Islands, and in an epidemic of dysentery in Germany by Kruse. 

 In 1903, Duval and Vedder found this organism in the discharges 

 of dysentery patients in United States, and in 1903, Duval and 

 Bassett, working at the Thomas Wilson Sanitarium near Balti- 

 more, Maryland, isolated this organism from the stools of children 

 suffering with summer diarrhoea. Since Shiga's discovery of the 

 organism, B. dysenteriae has been found in association with dysen- 

 tery in almost all parts of the world, and the etiology of bacillary 

 dysentery now seems well established. While at first it was sup- 

 posed that the different organisms isolated from stools in these 

 cases were the same, later investigation has shown that there are 

 two principal varieties of the species of Bacillus dysenteriae. Of 

 these the original Shiga isolation represents a strain which does 

 not ferment mannite, while the organism isolated by Flexner 

 represents a type which produces acid on mannite. The mannite 

 fermenting type has now been found to include at least two and 

 probably three different strains. The original Shiga type has 

 been found especially in the cases of epidemic dysentery in adults, 

 while the mannite fermenting types are most frequently found, 

 although not exclusively or as the only type, in the stools of chil- 

 dren suffering with summer diarrhoeas. The latter fact empha- 

 sizes the especial importance of the mannite fermenting types of 

 dysentery bacilli to the dysenteries in the United States. 



A further difference has been found between the two main 

 types; the mannite fermenting types do not produce an extra- 

 cellular toxin, while the type, not producing acid on mannite, 

 produces an extracellular toxin. Because of these differences 

 in the ability to produce extracellular toxin, antitoxic immunity 

 can be produced by experimental immunization for the Shiga 

 type, while for the mannite fermenting types the production of 



