132 THE POPULAR SCIENCE MONTHLY 



so much of the time that little is seen of it within the laboratory pre- 

 cincts. 



By seven o'clock the engine of the Sven Loven is warning ns by a 

 series of sharp explosions, accompanied by a cloud of dark smoke and 

 fumes from the burning crude oil, that everything is in readiness for a 

 collecting trip. We scramble aboard and Albert Henriksson, the 

 capable draggmastaren, swings the tiller around so that we head up 

 Gullmar Fjord. 



In the distance the hills rise from the water like banks of purple 

 mist while the nearer rocks are as clean cut as cameos. In an hour we 

 come to the deeper waters where under fifty fathoms the beautiful red 

 holothurians browse. Our object is to study the embryology of tbese 

 cousins of the star-fish and we get them with a trawl built like the 

 front half of an old fashioned bob-sled from which a long hood of net- 

 ting runs out behind. In a half hour the engine gear is shifted and 

 the piano-wire cable carrying the trawl is wound in. With rope and 

 tackle we lift the great mass of slimy ooze and organisms on deck, pick 

 out our holothurians, place them in a weighted box and again lower 

 them to the bottom, in the hope that eggs will be laid and fertilized 

 for our work on the unknown life-history of this species. 



Again by means of the fine meshed plankton net we seek some 

 ctenophores and in a short time a number of these exquisite ovoid 

 jelly-fishes are found in the glass collecting- jar at the blind end of the 

 net. Eacli bilaterally symmetrical body, transparent as crystal, is 

 propelled by eight meridional rows of minute paddles, which shimmer 

 in the sunshine like rainbows. At the upper end of the globular crea- 

 ture is a sac filled with clear fluid, in which delicately balanced otoliths 

 vibrate. What does the ctenophore feel when the microscopic otoliths 

 lightly touch the sensory cells? We know that this animal has a very 

 primitive type of nervous system and there is experimental evidence 

 that the apical organ responds to mechanical stimuli while it is indif- 

 ferent to light. To ascertain the nature and extent of ctenophore psy- 

 chology is a most difficult task. First must come the skilful, patient 

 stimulation of each part of the animal with the most delicate physical 

 apparatus and chemical reagents, varying the light, temperature and 

 other elements of the environment under all the possible conditions of 

 existence. The more difficult part however is the interpretation of the 

 observed results of experimentation. The investigator must now be 

 a philosopher, able to resist the inclination to regard the creature as a 

 mere mechanism because its behavior seems so simple, and on the 

 other hand not yielding to the temptation to project his own mind into 

 the ctenophore when he finds its responses are an elementary edition of 

 his own. That such primitive organisms have the psychic, just as they 

 have the assimilative excretory, respiratory and reproductive functions, 



