NO. IO COCKROACHES—ROTH AND WILLIS AI 
termine possible oxytocic, vasopressor, or antidiuretic effects with 
corpora cardiaca from Periplaneta and Leucophaea were inconclusive 
(Vogt and Hild im Scharrer, 1955). Scharrer (1955) suggests that 
further tests seem necessary to substantiate the positive results ob- 
tained with extracts of Blaberus. 
It is not out of place to mention the work of Scharrer (1945, 1949, 
I95I, 1953) on the development of cancer in Leucophaea maderae. 
She found that gastric cancer can be induced experimentally in this 
cockroach by severing the recurrent nerve; branches from this nerve 
innervate the foregut, stomach, salivary glands, and salivary reservoir. 
Roughly 75 percent of the operated insects developed tumors, the 
stomach being the most frequently affected organ. The digestive 
organs of an insect are structurally comparable to those of higher 
animals, and studies of this kind, employing the Madeira cockroach, 
may have significance in aiding our understanding of cancer in 
mammals, 
If a black beetle [Blatta orientalis] enters your room, or flies 
against you, severe illness and perhaps death will soon follow. 
Maryland superstition, 
Cowan (1865). 
XIII. DISEASES INCORRECTLY ATTRIBUTED TO 
COCKROACHES 
Cockroaches have been suspected of causing certain diseases or 
disseminating several disease agents which, on subsequent investiga- 
tion, have been found to have other causes or vectors. 
Beriberi—Van der Scheer (1900, 1900a) believed that this vitamin- 
deficiency disease was caused by a parasite that lived in the intestine 
where it formed a toxin that caused degeneration of the nerves. He 
suspected that part of the life cycle of the parasite was passed in 
Blatta orientalis. Melville-Davison (1911) came to a similar conclu- 
sion. He believed that an amoeba which lived in the intestine of the 
cockroach caused the disease. 
Brighi’s disease —Caudell (1916) cited a case in which this disease 
was believed to have been caused by drinking soda water in which a 
cockroach had decayed. 
Cancer.—Caudell (1916) quoted a Professor Nordlyset who 
claimed in 1913 that cancer was caused by drinking water in which 
cockroaches had oviposited. Fibiger (1913) and Fibiger and Ditlev- 
sen (1914) demonstrated that Periplaneta americana is a vector of the 
