180:J.] microscopical journal. 243 



Remove on tlie point of a needle, from the edj^e of a growing 

 mat, a small particle and mount it in alcohol (to avoid air hub- 

 hies), and the examination can then be carried on readily. 

 The plant is made up of fibres interlaced in every direction; 

 these are so long tliat it is not ])ossible to find both ends and they 

 are generally broken from their inner ends. These fibres are 

 called the "hypha'." They end in a row of round, bead-like, 

 spiieres called "conidia." The hy[)hie, which bear th.e conidia, 

 are called the ''aerial hypha-.'' Tiiese arise into the air from the 

 meshes of •'submerged hyphu-" wiiich are spread out in the nu- 

 trient fluid and thence al>sorb food. These are the three parts 

 of the plant body, which is thus a very sini)»le organism. 



Tlie aerial hyplue branch at their tips and these brandies, in 

 some cases, brancii a second or even a third time. Tiie ulti- 

 mate branches thus formed are called "basidia" and these 

 produce on little tips called "sterigma" the small spores 

 or ''conidia." The latter are thus buds of smaller size and we 

 see in them a very simple device for reproduction. Their min- 

 ute size fits them for enduring drought and also renders them 

 readily transportable. These si)ores are produced in a straight 

 row (Fig. 8), the lower one being the youngest. As a result of 

 this, the older ones can be blown away and no harm to the 

 germinating organ results. The number of spores in a row de- 

 pends on the age and the circumstances of dispersal, in older 

 filaments there may be a dozen or even more in a row. The 

 spores are protoplasmic bodies, but their minute size makes any 

 eff )rt to stain them and thus demonstrate their protoplasmic 

 character less useful tiian the method of cultivating them. 



The conidia will adhere to a needle drawn through the mass 

 and this can then be drawn through a vessel of Pasteur's fluid. 

 The act sows the conidia in the culture medium. In the 

 course of a few days, minuie white spots are seen in the fluid. 

 These are the growth from the spores. They can be taken up 

 in a pipette and placed on a slide. Under the low power they 

 are seen to be made up of innumerable threads radiating from a 

 common centre. In Figure 1, a view of this stage is sought to 

 be given. This complex of fibres is the mycelium. They are 

 the nutritive part of the organism, and at the first there is no 

 other ]>art. If you watch the growth of the white si)ots from 

 day to day, you will see that they increase in diameter and 



