Plate XVTIT 



Photograph of part of a window pane soiled by flies. Natiu"al size. 

 rt...(Z faecal deposits. b...b 'vomit ' marks. 



Fi 



Fig. 



Fig. 2. Photograph of a cage {\ nat. size) in which well fed flies had been kept. Its surface 



is covered by numerous 'spots.' The white ones {a) are frecal deposits and the lighter 



ones (/') with dark centres ' vomit ' marks. 

 Fig. 3. Photograph of a film preparation made from the crop contents of a fly three days 



after feeding on the blood of a mouse just dead of anthrax. The preparation consists 



of a nearly pure culture of non-spore bearing anthrax bacilli. 

 (Figs. 2 and 3 from Graham-Smith, Report to Local Goveriiiiwnt Board, No. 40, 1910.) 



