McKenney — On Luminous Bacteria. 



219 



Relations to Temperature. 



Aside from some observations as to the maximum, minimum and 

 optimum temperatures for light production, nothing has been recorded 

 as to the relations of photobacteria to temperature. If the phenomenon 

 of luminescence be primarily an irritabile function, we would expect to 

 find evidence of this in the relations of the organisms to temperature. 

 It must bo borne in mind, however, that the term irritability rather ex- 

 presses our ignorance than our knowledge of the phenomena usually 

 classed under that designation. And this is especially true for the lower 

 forms of life. 



In the subjoined tables I give the earlier as well as my own records for 

 the temperature minima, maxima and optima for both luminescence 

 and growth in the three species I have examined.* 



*Here and wherever else in my paper temperature records are given 

 they are according to the Centigrade scale. 



