PENICILLIUM GLAUCUM 103 



Percy Prankland uses glass wool instead of cotton. 



With the aid of these methods, moulds, yeasts, micro- 

 cocci, bacilli, and spirilla are found, all of which are con- 

 tained in greater or less quantity in the air, though their 

 distribution is not the same in all parts of the earth's sur- 

 face, nor at all times, either as regards quantity or quality. 

 For example, the author found that the Micrococcus pro- 

 digiosus grew in abundance on a paste medium in the Alps 

 (HoUenegg, Styria) in the month of September, 1891, 

 whereas in the months of July and August in the same 

 year no perceptible trace could be found. 



Penicillium Glaucum. — The Penicillium glaucum, or pen- 

 cil fungus, grows in the form of locks of cotton-wool, and 

 during sporulation forms a green fur of a peculiar musty 

 odour. Its mycelium consists of horizontally-arranged, 

 straight, or slightly undulating jointed filaments, from 

 which the spore-bearing liypha (Fruchthyphen) stand 

 vertically up, dividing at their upper ends into forks 

 (basidia) from which fine processes branch off {sterif/- 

 mata) in the shape of a hair pencil, and are segmented at 

 their ends into rows of fine globular bodies (spores or 

 conidia), which in the mass give the fur its green colour (see 

 fig. 4). Sterilised bread-pap is particularly well adapted 

 for the growth of the pencil fungus, which forms a fur upon 

 it, white at first, but afterwards taking on a fine green 

 colour ; but besides this it grows in all sorts of places where 

 as a rule only mould can develop. Gelatine is liquefied by 

 it. The growth of mycelium takes place very well accord- 

 ing to Wiesner at a temperature of 26° C. ; sporulation 

 progresses best at 22° C. 



The fungi appear on plate cultures first as threads 

 diverging from a point, and do not form sharply-defined 

 dark-coloured colonies upon the gelatine, but radiate out 

 over a considerable extent of surface. The spore-bearing 



