164 CARNEGIE INSTITUTION OF WASHINGTON. 



Experiment 5, June 26. — 101 bottles were filled with water from the Gulf 

 Stream, 10 miles west of Loggerhead Key — that is, water which probably had 

 not touched a shore while flowing 1,000 miles or more, remaining during this 

 time under practically uniform conditions. Sargassum was added and the 

 bottles set aside for 10 days. The results of the examination are shown 

 below. 



Experiment 6, June 26. — 104 bottles were filled with water as in experi- 

 ment 5. To each bottle was added a leaf of Sargassum having a surface of 

 about 2 sq. cm. The Sargassum leaves were all taken from a single, rapidly 

 growing piece floating by itself, which was gently lifted out of the water 10 

 miles west of Loggerhead and handled with sterilized instruments. A piece 

 of autoclaved Sargassum was added as usual. 13, 14, and 15 days later the 

 bottles were examined with the results shown below. 



Experiment 7, June 29. — A pit about 1 meter deep was dug in Sand Key 

 (Tortugas), which has no vegetation, a few centimeters below the low-tide 

 line and 100 bottles were filled with the water which seeped in. Sargassum 

 was added as in the preceding experiments. The results of the examination 

 12 days later are tabulated below. 



Experiment 8, June 29. — About 3 c.c. of undisturbed leaf mold from under 

 bay-cedar bushes was placed in each of 20 sterilized bottles filled with 

 sea-water. 13 days later they were examined with the results shown in the 

 table. 5 bottles similarly set up were autoclaved 30 minutes at 12 pounds 

 pressure as a control. 



Experiment 9, June 29. — 20 bottles were prepared as in the preceding 

 experiment except that about 20 dead Tournefortia leaves, still hanging on 

 the plant, were placed in the bottles instead of leaf mold of the bay cedar. 

 The results of the examination 14 days later are shown in the table. 



Experiment 10, June 29. — In each of 20 bottles prepared as in the two 

 preceding experiments, 1 c.c. of coral sand from the surface (not deeper than 

 1 cm.) of the beach, 10 meters above the high-water line and 4 meters from 

 any vegetation. The results of the examination 14 days later are shown 

 in the table. 



Experiment 11, June 29. — In each of 20 bottles prepared as in experiments 

 8, 9, and 10 was placed dried eel-grass (Thalassia) from thin, loosely packed 

 rows about 3 meters above the high-tide line, which had been lying undis- 

 turbed for several months at least. In each bottle the fragments of eel-grass 

 amounted to about 250 cm. long by 1 cm. in width. An examination 14 days 

 later gave the results shown in the table. 



Experiment 12, July 13. — 102 bottles were filled with surface sea-water, 

 taken about 200 meters northwest from the laboratory dock on Loggerhead 

 Key, where the water averaged about a fathom in depth. The wind had 

 been from the west and the northwest for about a week previously, and 

 considerable amounts of algae had been torn loose and swept up on the beach. 

 This stirring up of the water did not increase the number of amebas in the 

 surface layer, as the results of the examination 9 days later showed. See 

 table below. 



Experiment 13, July 13. — Control. 101 bottles filled with sea-water and 

 plugged with cotton were autoclaved at zero pressure for 10 minutes. After 

 the bottles had cooled a small piece of autoclaved Sargassum (zero pressure, 

 10 minutes) was added to each bottle and the plug replaced. No amebas, 



