MASON AND LEFROY. 17 



and described in the supplement to the Board of Agriculture Journal 

 for December 1908. 



The* stomachs are cut open as carefully as possible so as not 

 to injure the contents, which owing to partial digestion are as a rule 

 very liable to break up, and so, in the case of insects especially, 

 rendered much more difficult to identify. The stomachs are then 

 immersed in water, and the contents washed out into a white saucer 

 or what is still better a white porcelain photographic developing 

 dish (I plate size is the best for the smaller stomachs). The larger 

 and more easily identifiable portions of the food material are then 

 removed one by one, identified, and tabulated. All the unidenti- 

 fiable material is placed in bottles containing a weak solution of 

 spirit or formalin, or in the case of seeds is dried and then put up 

 in glass tubes. If the stomach contents do not wash out readily 

 it is best to scrape them out with a needle : a brush should not be 

 used, as with it insects are far more likely to be broken, and one 

 cannot see what one is doing nearly so well. After all the readily 

 identifiable material has been removed and noted, the water is run 

 off the dish, none of the material being allowed to escape, and clean 

 water is added. This is not necessary in the case of the stomachs 

 of the smaller birds, but is so with the larger ones and especially 

 if omnivorous, these latter always containing a large percentage 

 of semi-digested animal and vegetable matter. The rest of the food 

 is then treated and examined as described above. In the case of 

 the smaller birds it will often be found necessary to examine the 

 food or portions of it under a glass, and a magnification of 10 is 

 quite sufficient for the purpose. 



Stomachs should be examined as soon after they have been 

 obtained as possible. It is always a difficult matter to identify a 

 great deal of the contents of the stomachs, and if they have been 

 kept for any time in spirit, identification is still more difficult. This 

 is especially the case with caterpillars and any food material that 

 may have colouring matter in it, as this is usually destroyed by the 



* Here as elsewhere in this paper with reference to my own notes, the word ' stomac h' 

 is used to denote the whole alimentary canal t and not the crop and gizzard only. 



2 



