TOXICITY OF COAL. TAB CREOSOTE FOR LIMNORIA LIGNORUM. 
223 
was to be 30 minutes or more, the dish was stirred at 15-minute intervals, and the 
animals again distributed over the bottom. At the end of each experimental 
period the poison was decanted, and the animals transferred with about 300 cc. 
of sea water to a finger bowl, in which they were washed at least three times with 
large volumes of fresh sea water. They were finally allowed to stand for about 
24 hours in a large amount of sea water. The Limnoria in each lot were then 
examined individually under low magnification, and classified under one of six 
headings, as follows: 
1. Normal. — The Limnoria grouped here apparently were unaffected by the 
treatment. They crawled about and swam readily. 
2. Good. — The Limnoria in this group were able to crawl about actively but 
could not swim, though the swimmerets waved rhythmically with scarcely any 
intermission. 
3. Fair. — In this group were included the borers that could not crawl about, 
but in which there were leg movements and occasional waving of the swimmerets. 
4. Poor. — The borers in this class showed only sluggish leg movements, while 
all movements of the swimmerets had ceased. 
5. Very poor. — These Limnoria were moribund and showed only an occasional 
slight spasmodic movement of a leg or of a single joint. 
6. Dead. — The animals in this group were quite opaque, in contrast to the trans- 
lucent appearance of those which were graded “very poor.” 
CREOSOTE AND ITS FRACTIONATES. 
The first series of tests with the creosote and its fractions was carried out with 
sea-water extracts. The second series consisted of tests with emulsions. 
SEA-WATER EXTRACTS. 
The method of preparation of these extracts was as follows : Ten grams of the 
creosote preparation were intimately triturated with enough purified talc and clean 
sea sand to make a loose powder. To the latter were added 100 cc. of sea water; 
then the whole was shaken vigorously for 10 minutes and poured on a dry filter. 
The filtrates in all cases were perfectly clear. On these filtrates toxicity determina- 
tions were carried out in the manner already described. 
The experimental data are presented in the form seen in Figures 1 to 4 in order 
that the reader may obtain a quick estimate of the toxicity of a preparation with- 
out resort to comparison of numerical data. In each experiment the “T” column 
gives the several time periods during which the respective lots, of approximately 
25 animals each, were in the poison. Each asterisk (*) represents a single observed 
specimen of Limnoria. 
In the upper two rows of Figure 1 the aqueous extracts have been arranged in 
the order of diminishing toxicities as follows: Experiments 20 (Fraction I), 2 30 
(Fraction II), 26 (creosote), 46 (Fraction III), 45 (Fraction IV), 43 (Fraction V). 
2 At the time this experiment was carried out, a separate classification of “ very poor” specimens had not yet been made. 
In this respect experiment 20 may be compared with experiment 30 (top row, fig. 2). 
