The Nineteenth Century 225 



probable date of discovery. Space does not permit a reprinting of 

 Ehrenberg's table. Many of the early observations on particular spe- 

 cies will be found in the subsequent chapters of this book dealing 

 with luminescence in various phyla of animals. It must suffice to say 

 that Ehrenberg's compilation will always be of gieat value to every 

 serious student of light production by living things. His original 

 observations occupy forty pages of the book and are largely devoted 

 to the story of the discovery and descriptions of those microscopic 

 forms, the dinoflagellates, responsible for the diffuse luminescence of 

 the sea. Although Ehrenberg suspected that the light of dead fish 

 and flesh came from living things, the proof was not certain in 1834. 



Ehrenberg was fundamentally a student of protozoa and other 

 small forms. His interest in marine luminescence arose from the 

 suspicion that these organisms might cause the light of the sea, 

 observed during his travels. Born at Delitzsch, near Leipzig, Ehren- 

 berg first studied theology at Leipzig, then medicine and science at 

 Berlin. A six-years' voyage of exploration to Egypt and the east in 

 1820-1826 directed his interest to biology. He brought back im- 

 portant collections and in 1829 accompanied Gustav Rose and Alex- 

 ander von Humboldt on their Asiatic expedition. 



Ehrenberg's most productive years came before 1838, when his 

 Injusioiisthierchen als Vollkommenden Organismen appeared. This 

 work greatly advanced the knowledge and classification of protozoa, 

 but he adopted the idea that these forms were complete organisms, 

 with digestive systems, reproductive organs and other structures 

 found in higher multicellular animals. When the theory fell into 

 disrepute, Ehrenberg largely ceased active research. He was made 

 professor of medicine at the University of Berlin in 1839, and be- 

 came Permanent Secretary of the Berlin Academy of Sciences in 

 1842. The completeness of Das Leuchten des Meeres is a tribute to 

 Ehrenberg's historical talents, which developed quite early in life. 



HARTING, QUATREFAGES AND HELLER 



The middle of the century saw the publication of several general 

 papers on animal light, by Quatrefages in France, by the naturalist, 

 P. Harting in Holland, and by Heller in Germany. The Quatre- 

 fages and Heller publications were of real importance. The Pieter 

 Harting (1812-1885) contribution,-*^ " Het Lichten von Dieren " 

 was a twenty-five-page review in Album der Natur (1852) , a semi- 

 popular journal published at Haarlem. It contained figures of 

 well-known luminous or allegedly luminous animals such as the 



''^ A German translation. Das Leuchten der Thiere, by J. E. A. Martin appeared in 

 Skizzen aus der Natur in 1854. 



