70 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 134 
organism was fed together with bread and human feces. It passed 
through the insect unchanged. 
Cockroaches (presumably Blatta orientalis, Blattella germanica, 
and/or Periplaneta americana), Egypt (El-Kholy and Gohar, 1945) : 
S. typhosa isolated from macerated insects and from plates over which 
the cockroaches had walked after they had received an inoculated meal. 
Cockroaches, U.S.A. (Coplin, 1899): Cockroaches, which were 
allowed to walk over a culture of the organism, transferred S. typhosa 
to agar plates both from the feet and the ventral surface of the body. 
U.S.A. (Longfellow, 1913): Organism isolated from intestine and 
outer surface of body. Venezuela (Tejera, 1926) : Typhoid organism 
isolated from feces 24 and 48 hours after the cockroaches had eaten 
an inoculated meal. 
Serratia marcescens Bizio 
This species of bacteria is normally found in water, soil, milk, foods, 
and insects. It has been isolated from cockroaches several times and 
is known to be toxic to insects. Dr. T. Olson (p.c.) isolated, from a 
species of Periplaneta received in a shipment from the south, a strain 
of S. marcescens which was toxic to mice when administered intra- 
peritoneally. 
Shigella alkalescens (Andrewes) Weldin 
Disease.—Dysentery in man. 
Natural vectors——Periplaneta americana, U.S.A. (Bitter and Wil- 
liams, 1949, 1949a): Organism isolated from the intestinal tract. 
Shigella dysenteriae (Shiga) Castellani and Chalmers 
Synonymy.—B. dysenteriae Shiga of Pavlovskii. 
Disease.—Dysentery in man and monkeys. 
Experimental vectors.—Blatta orientalis, Italy (Spinelli and 
Reitano, 1932): The dysentery organisms passed unharmed through 
the digestive tract and were isolated from the intestinal tract and feces 
6 days and 96 hours, respectively, after an experimental meal; the 
organism was also regurgitated. 
Periplaneta americana, Formosa (Morischita and Tsuchimochi, 
1926): Feces of 30 cockroaches fed a culture of this organism were 
100 percent contaminated. Feces excreted 48 hours after feeding 
were mostly positive, and those after 58 hours were entirely negative. 
At dissection after 70 hours, the contents of the digestive tracts were 
all sterile. Cockroaches killed after 48 hours still contained the 
organism. 
