McKenney — 0)h Luminous Bacteria. 231 



4. There is no luminescence at or below 0°. 



5. Exposures to temperatures above the growth maximum are highly 

 injurious to the power of light production, while exposure to very low 

 temperatures seems to serve as a stimulus to light production. 



6. Bacillus i^hospJwrescens is capable of adapting itself to high tem- 

 peratures, producing a race capable of light production at 35°, which 

 is 5° above the normal maximum for luminescence. 



7. A certain degree of continued illumination is without etfect, and it 

 is possible for the bacteria to live their entire lives in the dark and yet 

 emit a brilliant light. 



8. Ether acts as a narcotic, preventing luminescence, but not growth 

 and multiplication. 



9. It is possible to develop a race of bacteria so immune to the action 

 of small amounts of ether as to be still luminous in its presence. 



10. Peptone or related protein is required for the nutrition of luminous 

 bacteria. 



11. Dextrose, and certain of the higher sugars may be utilized ad- 

 vantageously by Bacillus phospJiorescens. 



12. Either sodium or magnesium is required for growth, and especially 

 for light production. Minimum, maximum and optimum amounts of 

 sodium are observed for growth and luminescence. 



13. Potassium, ammonium, lithium, rubidium, calcium, barium and 

 strontium cannot replace sodium (or magnesium). 



