666 The Philippine Journal of Science 1922 
It is highly probable that sunshine is responsible for the 
destruction of eggs of Ascaris vitolorum in soil. Sunshine, 
because of its destructive action on the eggs and larve of hel- 
minths, is probably an effective natural weapon against depreda- 
tions of internal parasites. Exposure to sunshine of manure 
infested with ova and larve of helminths may prove effective, 
at least in the Tropics, in rendering it innocuous so far as 
concerns parasites. 
COMPARATIVE VIRULENCE OF ASCARIS VITOLORUM FOR GUINEA PIGS 
Experiments involving forced feeding of embryonated eggs 
to guinea pigs and rats showed that the effects produced on 
these animals were generally milder than those produced by 
the larve of Ascaris lumbricoides. Asa matter of fact, negative 
post-mortem results were obtained in several cases in which 
moderate doses of eggs were fed. Extremely heavy doses of 
eggs fed to guinea pigs produced symptoms of Ascaris pneu- 
monia, but deaths were not common. While I know of no ac- 
curate method by which to judge the relative effects of eggs 
of Ascaris lumbricoides and A. vitolorum on guinea pigs, I have 
reason to believe, basing my belief on results from experimental 
feeding of eggs of both species to these animals, that they are 
more resistant to the larve of A. vitolorum than they are to 
those of A. lumbricoides, so far as can be judged by recovery 
following an attack of Ascaris pneumonia. 
OCCURRENCE OF LARV4 IN VARIOUS ORGANS 
Observation on the invasion of the lungs and liver by the 
larve of Ascaris vitolorum revealed nothing that differs essen- 
tially from the invasion of these organs by the larve of A. 
lumbricoides, except that the liver remained parasitized for 
longer periods in animals infected with the former species. 
Larve were not found in the blood, which probably was due 
to the fact that the experimental animals that were examined 
within a day or two after artificial infection generally proved 
to be lightly parasitized. This was due in turn to the feeding 
of old cultures that contained many nonviable embryonated eggs. 
Larve were found in the liver as early as one day after artificial 
infection, but the lungs and other organs were negative in this 
early stage of infection. 
As has been mentioned the most-striking difference in be- 
havior of the larvee of Ascaris vitolorum and of A. lumbricoides 
is the comparatively longer sojourn of the former in the liver. 
In a recent paper on the course of migration of A. lumbricoides 
