Galvanometer 



Fig. 1. Apparatus for determining heat production during luminescence of 

 luciferin. A, special thermos tube. B, Dewar flask for constant temperature 

 junctions. C, copper double throw switch. D, tube containing luciferin solu- 

 tion. E, tube containing luciferase solution. F, glass rod for breaking E. 

 G, rubber stopper with groove, K, for puUey cord. H, cork closing thermos 

 tube. J, brass sleeve in H allowing rotation of E. L, thermo-couple in lucifer- 

 ase solution. M, thermo-couple in luciferin solution. N, constant temperature 

 junctions, 



139 



