582 W. BFAXLAND BENHAM. 



the glowworm, and firefly, and others). It has long been 

 regai'ded as connected with metabolism and rapid oxidation 

 of fat. Radziszewski has carried out a series of experiments 

 with various organic chemical substances, such as fats, 

 ethereal oils, hydrocarbons, and alcohols; and (I quote from 

 Max Verworn's 'General Physiology,^ p. 256) he "found 

 that a Avliole series of organic bodies emit light when they 

 are slowly combined with oxygen in an alkaline solution." 

 Further, Verworn states, '"'It is in the highest degree prob- 

 able that the luminosity of living substances depends upon 

 analogous processes;" and he comes to the conclusion, as 

 others have before him, that the photogenic substance is 

 produced in cell-metabolism. 



Now in the eleocytes of the coelomic fluid, it seems to me, 

 we have just the very conditions for the emission of light, 

 and we need not summon bacteria to their aid. As a matter 

 of fact, I have seen no bacteria in this photogenic fluid. 



The cells possess considerable vitality and power of resist- 

 ance to pressure and to drying, for after several hours' ex- 

 posure such a slime shows abundant cells of all kinds. In 

 one instance a living worm was first operated on at about 

 10.30 in the morning by a small incision ; it remained alive 

 in the dish, being repeatedly incised for fluid, all day, and 

 the slime, when examined at 4.30 the same afternoon, ex- 

 hibited all the usual cells apparently alive; at any rate the 

 amoebocytes were still moving, thrusting out pseudopods as 

 actively as when freshly extruded from the worm ; the cells 

 presented their normal appearance, and there was no evi- 

 dence that the linocytes discharge the thread, for the cells 

 were present in the usual proportion, and nothing resembling 

 empty cells existed. 



Again, tlie bottom of the tin in which several worms had 

 been kept for a week or more in grass, was covered with 

 slime, mixed with earth that had been discharged through 

 the anus. This dirty slime, when examined, also contained 

 uninjured cells ; but I was unable to detect many of the lino- 

 cytes. Some I saw, but apparently they were not as abundant 



