THE PARATYPHOID (IROUP 381 
Lactose and saccharose are not fermented. Numerous attempts have 
been made to classify the paratyphoid bacilH into several varieties 
upon the basis of the fermentation of carbohydrates other than those 
mentioned above, but the lack of agreement has proved as insurmount- 
able obstacle to their general acceptance. 
(6) Enzymes.— The members of the paratyphoid group do not pro- 
duce soluble proteolytic ferments, and they do not liquefy coagulated 
blood serum, gelatin, fibrin or egg albumen. Neither lipolytic nor 
amylolytic enzymes have been demonstrated in cultures of these 
organisms. 
(c) ro.Tins.— Soluble toxins have not been demonstrated in cul- 
tures of paratyphoid bacilli. Cathcart' and Franchetti- have shown 
that minute amounts of autolysates of the organisms are rapidly fatal 
to rabbits and other small laboratory animals. According to Cath- 
cart/ the poisonous substance (endotoxin) liberated from the organ- 
isms during autolysis is relatively thermostabile; a brief exposure of 
it to 100° C does not completely destroy its potency. Frei^ has shown 
that members of the paratyphoid group produce substances from their 
action upon meat proteins that cause contractions in isolated, surviving 
strips of rat intestine. 
Classification and Identification of the Paratyphoid Group. — It is pos- 
sible to di^•ide the Paratyphoid (iroup into two quite distinct types by 
their reaction in milk: The alpha type, of which several strains have 
been described, diflering somewhat in their serological reactions; and 
the beta type. The former appears to be limited to man, Init the 
latter comprises organisms which are rather widely distributed not 
only in man but in the lower animals as well. The better known 
strains of the beta type comprise not only B. paratyphosus beta, B. 
enteritidis and the hog cholera bacillus (B. cholera^ suis, B. suipestifer) 
mentioned above, but B. psittacosis, obtained from infectious enter- 
itis of parrots, which produces a pneumonic infection in man.-^ B. 
icteroides, Sanarelli, originally supposed to cause yellow^ iexer, but 
now known to be indistinguishable from the hog cholera bacillus, the 
Danysz bacillus of rat plague, and B. typhi murium, Loffler, obtained 
from epizootics of rodents, B. sertrycke, de Nobele and B. moorseele, 
van Ermengem, from epidemics of meat poisoning, and B. morbificans 
bovis, Basenau, isolated from a diseased cow, all belong to the same 
group. They possess in common cultural characteristics which differ 
somewhat quantitativeh', but not qualitatively. Bainbridge and 
O'Brien'^ have attempted to classify the organisms by agglutination 
and absorption tests; they recognize four groups as follows: (1) 
B. paratyphosus alpha; (2) B. paratyphosus beta; (.3) B. suipestifer 
' Jour. Hyg., 1906, 6, 112. •= Ztschr. f. Hyg., 1908, 60, 127. 
' Loc. cit. ^ Ztschr. f. Fleish. ii. Milchhyg,, 1920, 37, 98. 
^ Nocard: Conseil d'hygienc pub. ct Salubritc du Dept. du Seine, Seance, March 24, 
1893. 
6 Jour. Hyg., 1911, 11, 68. 
