200 
Ascaris lumbricoides 
Expt. 4. Sucking-pig No. 9. On 28. n. 17, when eleven days old, it was given 
a moderate dose of eggs 2-| months old, the culture had previously been proved 
infective to mice. On 14. in., it was killed, the stomach, small intestine and caecum 
were thoroughly washed out separately, the washings being repeatedly sedimented 
and rewashed, and finally examined on a dark surface; no worms were found. I am 
certain that no worm over 2 mm. in length would have escaped my observation. 
Expt. 5. Sucking-pig No. 10. On 28. ii., when eleven days old, it was given a 
small dose of the same culture as Pig 9. On 20. in. it was killed, but no worms were 
found in the intestine. 
Expt. 6. Pig No. 11. On 28. n., when 21 months old, it was given a large dose 
of culture 3 months old. On 9-10. in. it was suffering from marked dyspnoea and 
cyanosis; the temperature rose to 105° F. On 11. m. it had recovered, two dead and 
partially macerated Ascaris larvae being found in the faeces; the latter loaded with 
unsegmented Ascaris eggs. On 20. in. it was killed, and 38 $ and 19 $ Ascaris 
were found in the intestine, measurements of the females in mm. were: 250 (2), 
220 (2), 210 (3), 205 (1), 200 (1), 190 (1), 180 (1), 172 (1), 170 (3), 165 (4), 155 (5), 
145 (4), 140 (3), 135 (2), 125 (2), 105 (1), the bracketed figures denote the number of 
specimens of each measurement. The males measured between 160 and 65 mm. 
By way of commentary on the above I would note that the measure¬ 
ments form a fairly continuous series with the maximum numbers at the 
medium measurements, 145-170 mm. in 18 specimens. This suggests 
that the worms emanated from several infections that closely followed 
each other. It does not suggest an infection 20 days old superposed 
on one at least 50 days old. Also if these worms originated in the 
experiment it is necessary to suppose that a larva of 2 mm. grew to a 
worm of at least 105 mm. in 10 days. 
Expt. 7. Pig No. 12. On 28. II., when 21 months old, it was given a dose of eggs 
3 months old, rather fewer than were given to Pig 11; the culture had proved in¬ 
fective to mice. On 7. in. the animal was slightly dyspnoeic, its temperature 103° F. 
(normal 102-6° F.). On 30. in. it was killed and 22 Ascaris were found in intestine, 
their sex not being ascertainable from tail character. The measurements, in mm., 
were 70, 60, 45 (2), 42, 40, 37, 35 (2), 33 (4), 31 (2), 30 (2), 28, 27, 25, 20. 
I would note that these young forms may have originated from the 
eggs administered 30 days previously. Comparing their measurements 
with those of the worms from Pig 6 it is clear that if any of the former 
originated from the experiment none of the latter did and vice versa. 
Expt. 8 1 . Pig A. On 20. ix. 15, when aged 2 months 20 days, it received a small 
dose of A. suilla eggs. On 21. IX.-23. ix. the doses were repeated daily. On 13. x. 
15 it received large doses of eggs 57 and 64 days old. On 19. x. the pig’s respirations 
were rapid. On 20. x. it showed marked dyspnoea and fever lasting until 23. x. On 
24. x. it recovered. On 15. xn. the faeces having been repeatedly examined and 
no eggs found, it was killed, and I found one Ascaris, measuring about 80 mm., in 
intestine. 
1 See footnote p. 201. 
