234 Pennington — A Chcmico-Pliysiological 



blue violet. It may be then, that all the available energy 

 furnished by the violet rays is only sufficient to produce 

 this imperfect hydrolysis. Or, judging from the experi- 

 mental work cited, the violet rays are so detrimental to the 

 cell that its normal activity is reduced almost to zero. 

 Under the usual conditions, that is the less refrangible rays 

 being present also, their activity may overcome the injuri- 

 ous effects of the violet rays. Bolrytis cinerea, as shown 

 by Klein, is too sensitive to these rays to have their action 

 overcome by the presence of the red end of the spectrum, 

 and doubtless other plants would show the same phenom- 

 enon. 



The third day generally finds the cells attacked by bac- 

 teria. The very rapid increase of these organisms causes 

 complete disintegration of the cell contents, with the simul- 

 taneous production of an inky-black compound which fills 

 the cell cavity. By the sixth day the cells are quite empty 

 save for the black substance. 



The bacterial organisms never failed to make their 

 appearance under the violet screen, though the other cul- 

 tures were quite free from similar growths. They formed 

 an iridescent pellicle over the surface of the water, and 

 caused a foul odor, suggesting butyric acid. 



Through the kindness of Dr. Alexander Abbott, Director 

 of the Department of Hygiene, this pellicle was investi- 

 gated and found to contain four spirilla which did not 

 liquify gelatine, and whose characters do not agree with 

 those of any known form. Unlike other organisms these 

 flourish under violet light. Three of them are chromo- 

 genic, producing a pale yellowish-green color. 



Having proven that the cell under violet light could not 

 transform its starch into sugar, the question arose, Can the 

 de-starched, but otherwise healthy, cell produce starch 

 when exposed to violet light only? 



To answer this query material was rendered free from 

 starch and placed under the colored screen. At the end of 

 twenty-four hours the cells were still quite free from starch, 



