6 JOSEPH HALL BODINE AND PAUL RUDBERT ORR. 



desirable to a least make accurate quantitative analysis of the car- 

 bon dioxide and oxygen content of the culture bottles used in the 

 present experiments. 



Culture bottles were variously stoppered as indicated in Table I. 

 and analyses made of their carbon dioxide and oxygen contents. 

 In making the analysis the air samples were at first taken from 

 different levels in the bottles beginning just below the stopper and 

 finally just above the medium. No marked differences in the car- 

 bon dioxide and oxygen content of the air samples from differ- 

 ent levels in the bottles were noted except that when the sample 

 was taken at the surface of the medium slight differences in 

 amounts of the two gases were usually found. All samples used 

 and indicated in Table I. were taken from the middle of the cul- 

 ture bottles. 



An examination of this table shows that in bottles with cotton 

 plugs, gauze plugs, gauze stretched over the tops, etc., there were 

 no appreciable differences in the amounts of carbon dioxide and 

 oxygen noted. In bottles stoppered with cork or glass rather 

 marked increases in the carbon dioxide content and decreases in 

 the oxygen content were found. It must be pointed out here, 

 however, that in these experiments only carbon dioxide and oxygen 

 have been measured and that no account of other gases formed 

 has been taken into consideration. 



BEHAVIOR OF FLIES IN DIFFERENTLY STOPPERED BOTTLES. 



The behavior of flies kept in differently stoppered bottles as 

 noted by Pearl and Parker (3) is of considerable interest. These 

 authors found that in bottles stoppered with gauze the wild flies 

 tended to congregate at the top of the bottle under the bolting 

 cloth while no such behavior was noted in the case of the Quin- 

 tiple flies. This behavior in the case of the wild flies was not 

 noted in bottles stoppered with cotton. The increased amounts of 

 fresh air in the case of the bottles stoppered with gauze is -ivi-n 

 by these authors as the cause of this behavior. 



Experiments were carried out by the present authors to test the 

 behavior of wild flies in differently stoppered culture bottles 

 (capacity 100 cc.) but no significant differences were noted Asa 

 matter of fact if a cvlinder was made of wire gauze the same 



