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16,1 Haughwout and Horrilleno: Intestinal Parasites 55 
and which consequently must be as constantly renewed, appear to favor 
the view that Ascaris probably supplements its food intake by sucking blood 
from time to time * * *. In this connection it is interesting to observe 
that coincident with the disappearance of oxyhemoglobin from the worms 
in vitro they become sluggish, and that their existence after the complete 
elimination of this substance is very brief. 
Schwartz’s paper should be consulted by those who are in- 
terested in the details of the work that has led him to these 
conclusions. 
We feel compelled to end our discussion of Ascaris at this point 
with the comment that another feature presented by the pos- 
sibility of lung involvement in ascariasis will be the difficulty of 
diagnosis. Naturally, stool examinations in these early cases 
will prove nothing one way or another. This presents another 
problem to- the laboratory man. From the foregoing data re- 
garding the physico-chemical phenomena attending Ascaris in- 
fection it seems to be suggested that the reactions of the blood 
may prove to be a promising line of attack. It may develop 
that the differential blood count may show something charac- 
teristic during the lung stages of Ascaris development. Some- 
thing may even be done with sero-diagnosis. Already something 
has been done along the latter line in helminthal infections, 
notably in precipitin reactions and complement deviation in 
echinococcus infection and the complement deviation in parago- 
nomiasis. The work of J. G. Thomson (52) on the complement 
fixation in malaria is another instance of the promise of such 
work in connection with the animal parasites. 
Hookworm. — Only twelve infections with hookworm occurred 
in this series. The parasite occurred alone in but one case. 
In four cases it appeared accompanied by Trichuris, while Tri- 
churis and Ascaris were its companions in seven cases. Only 
one of these infections appeared in a child below 7 years of 
age. That was case 23, a girl 3 years old. Seven cases oc- 
curred in children residing in Manila, or 9 per cent of those 
living in the city who were in the series; and five cases, or 
21.7 per cent, occurred in children from the provinces. That 
is to say, the incidence of hookworm infection was more than 
twice as high in provincial as it was in urban children. The 
probable reasons for this are so obvious as to make it unneces- 
sary to discuss them here. 
Both Necator and Ancylostoma are found in the Philippine 
Islands. Their incidence and the phenomena accompanying 
hookworm infection in general have been studied and reported 
upon by competent observers. There has been found to be not 
