THE SCOLEX POLYMORPHUS 841 
the time nor the material for trying a modification of the treat- 
ment upon any considerable number of sharks. Only nine 
sharks were differently experimented upon and the results 
obtained are represented in table 6, the net results of which are; 
without infection, 5; found dead but in sufficiently good condition 
to give reliable evidence that the worms had been killed by the 
drug, 3; escaped, 1. 
The results of all the expurgation experiments may be summar- 
ized in the table which follows: 
TABLE 8 
Showing net results from all experiments in treatment with oil of male fern 
| SHARKS WHICH DIED UNDER THE TREATMENT, 
SURVIVING SHARKS | BUT IN WHICH THE WORMS WERE ABSENT OR 
HAD BEEN KILLED BY THE OIL OF MALE FERN 
TABLE REFERRED ol eae uf Cee eee 
| No infection | Still infected | mae sess er ‘Found dead Total 
| 
| 
1 4 if 5 
2 3 1 1 5 
3 4 6 3 4 17 
4 5 4 1 10 
5 5 Pe 4 11 
6 5 3 8 
| 
f ; Peis 
26 2 13 | 5 | 56 
In this table, a few specimens which were found dead and so 
decomposed as not to yield reliable data are omitted. The speci- 
mens which survived treatment are of course most important 
and stand in the proportion of 26 for and 12 against the success 
of the attempted expurgation. Of the non-surviving sharks we - 
have 13 specimens taken while still alive and all showing that 
worms were killed, as a result of the treatment and some time 
prior to the death of the shark. When one compares the number 
of worms found in these treated sharks with the tables and records 
showing their prevalence in sharks which have had no such treat- 
ment, it will be quite evident that a large proportion of the 
parasites must have been eliminated even by the single dose. 
