20 The Philippine Journal of Science 1915 
surrounded by a shell composed of 2 thin tough layers of chitin 
with a thick outer albuminous layer raised into blunt knobs or 
mammillations. In addition to this form, the various atypical 
forms which are sometimes encountered in feces were also 
found in the laboratory. The smooth eggs without an outer 
albuminous layer of shell, which have sometimes been considered 
to be the eggs of another species of Ascaris, are the commonest 
atypical form. They are always laid in the laboratory after 
the worm has been kept in Kronecker’s solution for some days, 
and are undoubtedly due to the failure of the glands of the 
uterus to function on account of lack of nourishment. Among 
the eggs obtained from 56 female ascarids, the first laying 
consisted of typical mammillated eggs in every case except one 
in which eggs were laid. In those cases where the worm con- 
tinued to lay eggs the albuminous layer became thinner and 
in the last layings obtained disappeared entirely. 
THE DEVELOPMENT OF THE EGGS 
The time required for development of the eggs under natural 
conditions is much shorter than in countries farther north. 
Most European and American authors state that the time of 
development is from several weeks to six or eight months. 
During March, April, and May eggs developed in from ten to 
fourteen days when kept in the laboratory at the ordinary 
temperature.” The eggs developed more rapidly and more reg- 
ularly on the surface of moist earth or on earth covered with 
a thin layer of water than in any other medium. Development 
was also rapid in tap water, pond water, and Kronecker’s solu- 
tion when the eggs were spread out in flat dishes. In distilled 
water the development was very irregular, most of the eggs 
dying before the embryos were formed. In solutions containing 
0.5 per cent of hydrochloric acid, 0.5 per cent of carbolic acid, 
or 3 per cent of acetic acid, the eggs commenced their develop- 
ment very quickly and developed at first very rapidly, but after 
a few days development ceased entirely and the embryos died. 
Since performing these experiments, I have read of some work 
on the development of the eggs of the pig and calf ascarids 
in which solutions of various acids of the strength of 1 part 
in 1,000 were used, with the result that the development was 
very much accelerated and continued until the embryos were 
* The most rapid development I have found reported is by Leuckart, who 
developed the eggs in fourteen days by keeping them in an incubator at 
30° C. 
