CONTENTS 



duction of electricity, p. 93 Electricity regarded as a form of 

 matter, p. 97 Radio-activity, p. 97 The nature of emanations 

 from radio-active bodies, p. 102 The source of energy of radio- 

 activity, p. 106 Radio-activity and the structure of the atom, p. 

 108 Effect of radio-activity upon heat-giving life of the sun and 

 the earth, p. in. 



CHAPTER V 



THE MARINE BIOLOGICAL LABORATORY 



The aquarium, p. 113 The arrangement of the tanks and exhib- 

 its, p. 114 The submarine effect of this arrangement, p. 115 Ap- 

 pearance of the submarine dwellers in their natural surroundings, 

 p. 116 The eels and cuttle-fishes, p. 116 The octopuses, p. 117 

 The technical department of the laboratory, p. 119 The work of 

 Dr. Anton Dohrn, founder of the laboratory, p. 121 The associ- 

 ates of Dr. Dohrn, p. 122 The collecting of surface specimens, p. 

 123 Collecting specimens by dredging, p. 124 Fauna of the Bay 

 of Naples, p. 124 Abundance of the material for biological study, 

 p. 125 Advantages offered by marine specimens for biological 

 study, p. 126 Method of preserving jelly-fish and similar fragile 

 creatures, p. 127 Uses made of the specimens in scientific study, p. 

 128 Different nationalities represented among the workers at the 

 laboratory, p. 130 Methods of investigation, p. 131 Dr. Diesch's 

 studies of heredity at the laboratory, p. 131 Other subjects under 

 scientific investigation, p. 132 The study of chromosomes, p. 133 

 Professor Weismann's theory of heredity based on these studies, 

 p. 133 Experiments in the division of egg-cells, p. 134 Experi- 

 ments tending to refute Weismann's theory, p. 136 Dr. Dohrn 's 

 theory of the type of the invertebrate ancestor, p. 137 Publica- 

 tions of the laboratory, p. 139 Meetings of the investigators at 

 Signor Bifulco's, p. 141 Marine laboratories of other countries, 

 p. 142. 



CHAPTER VI 



ERNST HAECKEL AND THE NEW ZOOLOGY 



The "dream city" of Jena, p. 145 The old market-place, p. 147 

 The old lecture-halls of the university, p. 148 Ernst Haeckel, p. 

 151 His discoveries of numerous species of radiolarians, p. 153 

 The part played in evolution by radiolarians, p. 156 Haeckel's 

 work on morphology, and its aid to Darwinian philosophy, p. 156 

 Freedom of thought and expression in the University of Jena, p. 157 



V 



