112 LIVING LIGHTS. 



action, and dependent upon the life of the bird ; and the 

 areas of the powder-down patches may be considered true 

 photogenic structures. The bird shot and examined by Mr. 

 Worrall was known to him as the blue crane, and I assume 

 from his description that it is the Ardea ccerulea. The other 

 birds in which the light was observed were night herons. 

 The light was in the so-called powder-down patches, which 

 form a characteristic feature of the herons, and doubtless 

 serve the same purpose, as a lure, in all. 



In a night heron, which I recently obtained from a valley 

 among the foothills of the Sierra Madre range, there were 

 three of those patches, and any heron will show them. One 

 is directly in front upon the breast, while the other two are 

 upon each side, midway between 'the base of the tail and 

 the upper portion of the thigh-bone. They are not visible 

 unless the feathers which cover these portions are brushed 

 aside, when a mass of oily small plumes are seen, of a 

 decided yellow hue, growing closely together, and about two 

 inches in length. A yellow powder will be found profusely 

 mixed among them, and is due to their barbed tips breaking 

 off as fast as they develop. 



In my specimen, just after death the patches were quite 

 oily, the substance coming off upon the hands, and smelling 

 like ordinary bird oil. As soon as possible I took the bird 

 into a perfectly dark room, to test it for phosphorescent 

 light, but not the slightest gleam was perceptible. Just 

 under the patches a large accumulation of fat is seen ; and 

 from these portions probably exudes the substance, which, 

 during the life of the bird, becomes luminous upon exposure 

 to the air. In the specimen alluded to, after it had been 

 dead for several days, the shafts of the feathers of the patch 



