49- 



Jonnial of Agriculiure, Victoria. [lo Aug., 191 2. 



INOCULATING NEEDLE. 



FIG. 8. INCUBATOR. 



method is — Glas.s te.st 

 tubes are taken, and 

 material, of which 

 gelatine forms a basis, 

 is introduced intothem. 

 Certain " food " is 

 added in the shape of 

 meat broth, egg albu- 

 men, &c., and all life 

 is destroyed in this 

 substance by means of 

 heat. That all life 

 is destroyed may be 

 shown bv the fact that 



Dyes are used, and counter stains, 

 it being found that different tissues 

 absorb or dye more readily with 

 certain colours than others. It 

 is thus possible to obtain contrasts. 

 They then have to be magnified 

 very considerably imder a micro- 

 scojie. Consequenth , it can be 

 readily understood that very few 

 of the organisms can hi definitely 

 recogjnised by merely examining 

 them under the microscope, and 

 further means are necessary for 

 identification. These include 



cultivation, for nearly all organ- 

 isms are capable of growth outside 

 the bcdv on special soil (Fig. 6) 

 media. Just as it is necessary 

 for the farmer, when sowing hi.s 

 wheat in a field, to have nourish- 

 ment, moisture, and warmth for 

 the growth of the wheat, so it is 

 necessary for these three things to 

 be present in order to produce a 

 crop of organisms. A great dif- 

 ference, however, exists in the 

 time occupied in growth, and also 

 in the number which can be pro- 

 duced from the original amount 

 introduced into the medium. The 



ITG. 9. 



PLATE CULTURES WITH CHARACTERISTIC 

 GROWTHS. 



