DERRIS AS A PARACITICIDE 43 
profuse, watery diarrhea was noted, the nose was dry, respiration rapid, 
and the animal gave every symptom of high fever. Thirst seemed 
insatiable, the animal lying by the water container and drinking repeat- 
edly. In all cases but one, death ensued within three or four days, 
the body being exceedingly emaciated. The surviving case had been 
given a rather smaller dosage (three pinches only, one applied to the 
belly and two to the back). This animal recovered from the effects 
of the derris but never again became vigorous. It died about a month 
later from a pulmonary infection with which it had previously suffered. 
There can be little doubt that the severe illness due to derris poisoning 
considerably hastened its death. The powder acts as an internal poison, 
being licked off the fur by the animals in grooming their coats. 
The pure powder was used-rather sparingly on a full grown cat 
for the flea, C. felis. The animal was completely rid of the insects, 
and seemed to suffer but slight inconvenience. There was no sign of 
the diarrhea so pronounced in the rats, but some symptoms of a feverish 
condition in its dry nose and a desire to drink. The cat was fully 
recovered in forty-eight hours and suffered no further inconvenience. 
The amount of powder used per unit of body weight was considerably 
less than with the rats, approximately one fourth to one third, it is 
estimated. No attempt was made to weigh the powder, as the inevit- 
able wastage in applying it made such a procedure seem a useless check. 
With a small puppy, about the same size as the cat used, so far as 
could be noted, the powder produced no ill effects, and was certainly 
effectual in removing the fleas, C. canis, with which the animal was 
heavily infested. On both the cat and the dog, the powder was applied 
in generous pinches on the back, belly, and flanks, and rubbed in by 
stroking the animal against the “lay” of the fur. On both the cat and 
the dog the insects were quickly stunned, dropping to the paper upon 
which the animal was placed and, so far as noted, never recovered 
more than enough to crawl weakly for a short time. 
Following this series of tests with the pure derris powder, similar 
experiments were made with the various diluted powders. Ail were 
found more or less effective, but there was considerable variation in 
their efficiency and time of reaction. Rats were again largely used as 
experimental animals, both because they were easier to handle and to 
keep, and because they were more easily reinfected after having once 
been cleared of parasites. The insects tested against were again the 
rat louse and the rat flea. The general results are discussed in the 
following paragraphs. 
