428 STUDIES IN GENERAL PHYSIOLOGY 



in Eudendrium racemosum more closely in Woods Hole. 

 The results of these observations are briefly reported in the 

 following pages. 



II. NEW EXPERIMENTS 



1. The species of Eudendrium studied in Woods Hole 

 has the same name as that in Naples namely, Eudendrium 

 racemosum; it is, however, not certain that the two forms 

 are identical. The following statements hold for the form 

 in Woods Hole. When fresh stems of Eudendrium are put 

 into an aquarium, all the polyps soon fall off, probably due 

 to unavoidable injury in collecting and handling the mate- 

 rial. In the course of a few days, however, with a good 

 supply of oxygen and a sufficiently high temperature, new 

 polyps are developed. It was the dependence of this new 

 development on light which was studied. 



A large quantity of vigorous colonies was collected each 

 time. Long stems were picked and put in separate vessels, 

 ten being distributed into each vessel, all of which contained 

 an equal quantity of sea- water. Each of the stems usually 

 formed from ten to twenty polyps. The different vessels 

 were exposed to various kinds of light. In each experiment 

 I therefore dealt, not with the development of a single 

 polyp, but with a large number of them. I thought it 

 necessary, furthermore, to make another set of control ex- 

 periments by exposing the same stems successively to differ- 

 ent kinds of light. 



Experiment 1. On August 8 a number of stems of the 

 same culture of Eudendrium was divided as equally as pos- 

 sible between two vessels, in the manner described above. 

 One of the vessels was exposed to diffuse daylight; the other 

 was placed in a dark box which was ventilated every even- 

 ing. The supply of oxygen was the same in the light as in 

 the dark, and the temperature was always the same in the 

 two vessels. 



