12 MEETING OF [WSPECTOB8 OF APIARIES. 



• loin. as the trees, shrubs, flower-, and grasses, and we may for con- 

 venience refer to these plant- as the \dsible flora. There is also an 

 invisible flora, made up of the plants we can not -re except with the 

 aid of the miscrope. Thi- flora include- the very minute plants 

 referred to a- bacteria, and also the yeasts and some fungi. The dis- 

 tinct species of plants which belong to the invisible Mora outnumber 

 by far those which are visible to the naked eye. These microscopic 

 plant- are found upon the surface of the animal body and along the 

 digestive tract : they are found in the -oil. in the food we eat. and in 

 the water and milk we drink, but are not found within the normal 

 tissues of animal- and higher plant-. 



IIoW BACTERIA AUK STUDIED. 



The morphology or structure of bacteria i- studied with the aid of 

 a microscope of high magnification. Since the number of distinct 

 species of bacteria i- so extremely large, and since the shapes assumed 

 by them are so lew. it i- obvioii- that many different kinds must look 

 alike under the microscope. This is a point of considerable value in 

 connection with bee-disease work, since in some cases attempt- have 

 been made by the use of the microscope alone to determine what 

 species of bacteria was causing certain diseased conditions. With 

 our present knowledge it is not possible to make a positive diagnosis 

 of these diseases with the microscope alone. With the microscope we 

 are able to determine usually only the genus to which any bacterium 

 belongs. If we are trying to identify Bacillus alvei, for example, we 

 arc able with the microscope alone to say only that it is a Bacillus. 

 since it is -ecu to be a straight rod. Some other means is necessary to 

 determine the specie- (alvei) to which it belongs. For this purpose 

 we use artificial media or "soils" in which pure cultures of the bac- 

 teria are inoculated or planted. 



The media in common use are bouillon and sugar-free bouillon. 

 gelatin, agar, and sugar-free bouillon to which ha- been added -mall 

 amounts of various sugars known in chemistry a- glucose, lactose, 

 saccharose, maltose, and levulose. In addition to these media, use is 

 made of potato, milk, and milk to which litmus ha- been added, so 

 that the reaction — whether acid, alkaline, or neutral — may be noted. 

 The bouillon is prepared from beef juice to which some peptone and 

 >-a\\ are added. Sugar-free bouillon is similar, except that the muscle 

 sugar ha- been removed. Gelatin i- made from pure -beet- of gel- 

 atin somewhat similar to that used in cooking, to which bouillon i- 

 added. The bouillon affords the food for the bacteria or other -mall 

 plant-, while the gelatin keep- the medium solid at ordinary tempera- 

 ture-. Agar-agar (or simply agar) i- the dried -tern of a certain sea- 

 weed which liquefies on heating; to this is added bouillon, as in the 



