The Seventeenth Century 115 



sidered, and Bartholin concluded that smoothness does contribute 

 to the " external light of waters," apparently a reference to reflec- 

 tion of light which he called " fulgor " as distinct from the emission 

 of light. " But back to the animate beings, which are believed to 

 shine from water and dew. . . . Dew has no color nor shiny effect." 

 It cannot produce splendor in animals by itself, because it is lack- 

 ing in light, as is easily observed when taken up by the body. If it 

 illuminates brightly it does so by the benefit of the enclosed light. 

 " And I gladly admit that light, the companion of air, is taken up 

 by dew as an appropriate subject. . . ." 



" But shining animate beings do not shine with some whitishness 

 or brilliance with which they could have been endowed by dew, 

 but manifest themselves with real light which communicates itself 

 also to the surroundings," that is, with the inherent light, charac- 

 teristic of all things. 



Even the obvious connection between putrefaction and luminous 

 fish, flesh, and wood was not considered a direct one. Bartholin (in 

 Problema III) held that the light was not " begotten by putrefac- 

 tion but only laid open," that putrefaction only " liberates the 

 latent seeds of light which had been suppressed in the mixture of 

 the elements." These quotations will suffice as examples of the 

 reasoning current in the mid-seventeenth century. 



Although Bartholin's explanation of the widespread distribution 

 of luminescence was by the simple assumption that light is a prin- 

 ciple associated with matter in general, this point of view is by no 

 means entirely new. Gregor Reisch (fl. end of fifteenth century) 

 attributed an inborn light to all living things in his encyclopedic 

 work, Margarita Philosophica (Heidelberg, 1496) . The belief was 

 widespread in medical circles that the heart was like a flame, as 

 expressed in the title, De Flammula Cordis (1667) of T. Bartholin 

 and Jacob Hoist. 



It is not possible to say that Thomas Bartholin introduced any 

 fresh point of view for the interpretation of luminescence, or other 

 wonders which he observed on his travels. De Luce Animalium is 

 full of Biblical references. Bartholin believed implicitly in the con- 

 version of Lot's wife to salt, citing instances of people turned to 

 stone in more recent times. He believed in many strange things, 

 including spells and charms for sickness— part of the widespread 

 credulity of his day— an attitude which shows only too clearly in 

 the previously quoted statements on the origin of the light of ani- 

 mals. Nevertheless, as author of the first comprehensive book on 

 luminescence, he deserves a prominent position in our history. 



