THE SCOLEX POLYMORPHUS 843 
infections, to let them all run as long as possible, but because the 
sharks first infected were kept to run longest; while later infec- 
tions were planned for the earlier stages, an arrangement which 
would give the most extensive time results in a limited time. 
When, however, the time came for infecting the sharks from 
which to secure the earlier stages, the squeteague could not be 
obtained in numbers sufficient to yield the larvae for infection 
purposes. 
Of the nine specimens, two died in the cars and from one of 
these two no data were obtained, so there are only seven speci- 
mens from which entirely reliable conclusions can be drawn. 
The sharks used were all starved for three or four weeks after 
their capture and then given 2 ce. each of the oil, followed twenty- 
four hours later by about 0.5ce. of calomel. They were all 
specimens which had survived this treatment and the history 
of each individual previous to the time of the infection is given 
in the first half of table 7. Since there is no evidence connecting 
the genus Crossobothrium with the 8. polymorphus, this table 
may also be used to furnish data on the success of the attempt at 
expurgation. The first part of the table gives the dates of cap- 
ture and of the treatment with the drugs, between which events 
the sharks were kept in the cars without food. The dates at 
which they were fed are also shown for comparison with the dates 
of infection. Each shark is numbered, as in the previous tables, 
and these numbers are repeated in the second half of this table 
where the results of the examinations for parasites are tabulated 
in a manner similar to that followed in the tables for treatment 
with the oil. 
In introducing the S. polymorphus into these sharks I took the 
portion of the cystic duct containing the larvae from twelve 
squeteague, and placed these in the little sac obtained by cutting 
off the end of a squeteague’s stomach. This sac was turned wrong 
side out to avoid any possible injury from direct contact with 
the mucous membrane of the squeteague. The infection thus 
prepared was introduced into the shark’s stomach by pushing it 
through a piece of iron pipe having a diameter sufficient to 
admit such an object without undue pressure. For food, I used 
