78 BULLETIN 208, UNITED STATES NATIONAL MUSEUM 



of it, does take place can no longer be doubted, but the manner of 

 that digestion is not yet clearly understood. There are two methods 

 by which this digestion might be effected: by wax-breaking intestinal 

 bacteria, or by some as yet undescribed and unusually powerful 

 enzyme. While the problem of how the wax is digested is of less im- 

 mediate concern, as far as the life history of the birds is concerned, 

 than is the fact that this hitherto supposedly indigestible substance is 

 really utilized as a source of food by them, nevertheless it is one of 

 very real interest and is being studied further. 



The possibility of bacterial activity is suggested by data on analogous 

 cases of insects that feed on beeswax, such as the waxworms of the 

 microlepidopterous genus Galleria, some species of which consume 

 wax as a regular and even large part of their diet, and some roaches 

 of the genus Blatta which do so occasionally. Wigglesworth (1939, 

 p. 280) states that the diet of Galleria larvae, which feed on honey- 

 comb, consists to a very large degree of wax, and he suggests that 

 "possibly the breakdown of some of the components is begun by 

 bacteria present in the gut." He further writes that the honeycomb 

 is about 60 percent wax, the excreta of the bees about 28 percent wax, 

 and that "part of the wax is certainly utilized. This fraction is 

 variously estimated as 34-43 percent and 50 percent. It is believed 

 to comprise all the alcohol components of the wax, a part of the fatty 

 acids and esters of high molecular weight, but none of the paraffins." 

 With the assistance of Dr. W. Buttiker, who was residing in Southern 

 Rhodesia, some 26 live cultures were made of organisms from the 

 alimentary tract of a greater honey-guide. These were flown to 

 Washington where they were identified and tested by Dr. Joel Warren 

 and Maj. Ray Cowley of the Department of Bacteriology, Ai-my 

 Medical Service Graduate School, Walter Reed Army Medical Center. 

 The strains included Aerobacter aerogenes, Pseudomonas cutirubrum, 

 Bacillus Jirmus, Escherichia intermedium, Paracolobactrum sp., and 

 unidentified strains of Enterobacteriaceae and Bacillaceae. None of 

 them showed any evidence of possessing any effect on beeswax or of 

 requiring wax for propagation. These bacterial strains represent the 

 common flora of the gastrointestinal tract of many mammals and 

 birds, and do not necessarily include all of the organisms present in 

 the honey-guide gut, but were the only ones received in viable or 

 uncontaminated condition in Washington. 



Evidence for bacterial action in the digestive process is not want- 

 ing in other birds, and this further suggests that some such condition 

 may apply to the honey-guides. Thus, Teichmann (1889, p. 235) 

 reports bacteria in the crop of the domestic pigeon that help to break 

 down carbohydrates and to form lactates. Kern (1897) records 



