. The Biological bulletin. Biology; Zoology; Marine biology. 238 LEONARD P. SAYLES After the first transfer to dilute sea water the same worm had increased about 50 per cent after 24 hours. Five days after the return to the dilutions the worms were again placed in ordinary sea water. The weight of C dropped suddenly even below that of the control. Both experimental worms then increased in weight a little and at the end of the experiment they were quite close to the control worm. Experiment 4. Effect of Gradual Dilution of External Medium Figure 4 gives an example of a worm which was weighed at
. The Biological bulletin. Biology; Zoology; Marine biology. 238 LEONARD P. SAYLES After the first transfer to dilute sea water the same worm had increased about 50 per cent after 24 hours. Five days after the return to the dilutions the worms were again placed in ordinary sea water. The weight of C dropped suddenly even below that of the control. Both experimental worms then increased in weight a little and at the end of the experiment they were quite close to the control worm. Experiment 4. Effect of Gradual Dilution of External Medium Figure 4 gives an example of a worm which was weighed at least once or twice between successive changes. Each change except the last was, of course, a relatively greater drop in salt content than was I50r. ISO 200 250 TIME-IN HOURS 350 400 Fig. 5. Effect of gradual dilution of the external medium. Average of 5 speci- mens. Period in each dilution indicated by the fractions as in Fig. 4. the one preceding it. As one might expect from this fact, the increase in weight was greater and the duration of the rise longer each time than it was the time before. Another experiment of this type, in which practically no weighings were made between changes, is shown in Fig. 5. Even here the changes were probably made too often. Unfortunately it became impossible to follow the weights of these worms beyond the fifth day in 1/8 sea water. At that time one was killed. The other four were moved from Woods Hole to New York City. Of these, one lived 10 days in the 1/8 sea water and the other three survived 14 days in that dilution. The fact that the thirteenth and fourteenth days were very warm and that no facilities were available for keeping the water at an even relatively cool temperature. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Lillie, Frank Rattray, 1870-1947; Moore, Ca
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectb, booksubjectzoology
