476 JOURNAL OF ECONOMIC ENTOMOLOGY [Vol. 17 
divide again by 100 as one gram of powder was introduced into each 
flask. The final table of solubilities would therefore be: 
Oesophagus 
As 2 —.0003232+ grams or .032% 
As 2 O s —.0004957+ grams or .049% 
Honey Stomach and Stomach 
As 2 —.0004155 + grams or .041 % 
As 2 0 5 —.0006373+ grams or .063% 
Intestine 
As 2 —.0012005+ grams or .12% 
As 2 O s —.0018412 + grams or .184% 
Check 
As 2 —.0003232+ grams or .032% 
As 2 0 5 —.0004957 + grams or .049% 
Check (water sol.) 
Since the quantities are so minute they are w r ell within the limits of 
possible error, and must be taken as mere indications of the effect of 
digestive fluids upon arsenate of lead powder rather than looking upon 
them as absolutely accurate or fixed quantities. For this reason it 
would be better to express the solubilities with reference to the water 
soluble arsenate of lead. Taking this as a unit we have 
Check (water sol.) 
As— .032% = 1.00 
As 2 O s — .049% = 1.00 
Oesophagus 
As— .032% = 1.00 
As 2 0— .049% =-1.00 
Honey Stomach and Stomach 
As— .041=1.28 
As A— .063 = 1.28 
Intestine 
As—.120% =3.75 
As 2 0— .184% =3.75 
Summary 
1. The hydrogen ion concentration of the alimentary tract of the 
honey bee is as follows:—oesophagus 7.0 (?), stomach plus the honey 
stomach 5.6, and intestine 7.4. 
2. The results of this experiment can only be an indication of what 
goes on in the insect’s body, for in carrying out this work some of the 
soluble arsenic combined with the cell protoplasm and could not be 
found in the filtrate. Furthermore, natural conditions could not be 
simulated so that it is probable that even more arsenic would be ren¬ 
dered soluble by the living insect. 
