M. C. COOKE ON MICROSCOPIC MOULDS. 51 



hands. This is demanding more than it is reasonable to expect; 

 and yet there are some who think that mycelium threads, or even 

 joints of such threads, found in different parts of the human body, 

 accompanying certain forms of skin or other diseases, deserve a 

 name and a character, although all the threads and cells ever yet 

 found in such positions may or may not be elementary conditions 

 of some very common mould, such as Aspergillus glaucus. The 

 flocci, or erect stem-like threads, which proceed from the mycelium 

 in the Polyactis are coloured, whilst in most of the true Mucedines 

 they are colourless. At certain distances these threads have trans- 

 verse septa throughout their length, and in the upper portion they 

 are branched, the ultimate ramuli or final branches, bearing terminal 

 clusters of spores. When the spores fall away little points or 

 minute spicules are visible to which the spores were attached. 



I must beg of you to compare together all the figures before you, 

 and, apart from the mycelium, to recognise the features in which 

 they agree. Of course all of them have fruit or spores ; that is 

 the one essential of a perfect plant. A fungus may consist of 

 nothing more than a delicate mycelium and a spore, but without 

 the spore — the great essential — it is an imperfect fungus, and can- 

 not be accurately determined. The most important organ, then, in 

 the determination of fungi is the spore. Young students are cau- 

 tioned against attempting to find a name for fungi if they cannot 

 first of all find the fruit. In the figures before us we have the 

 spores borne upon threads, which may be very short, almost obso- 

 lete, as in Macro spo rium ; or fully developed, but unbranched, as in 

 Aspergillus ; or branching as in Polyactis, and many others. Here 

 we have the features of the family to which these moulds belong — 

 ' Filamentous,' or thread-like, ' the fertile threads naked,' or 

 exposed, ' simple or branched, bearing the spores at their apices.' 

 It will be noticed that the spores are not enclosed, two or more of 

 them together in a vesicle, as in the fungi of a similar habit be- 

 longing to the Physomycetes, and this is the only caution needed, 

 for the thread-like form with terminal spores is not met with 

 in any other family. 



" Moulds " is a term, then, which I desire you to accept on this 

 occasion as representing the family name of Hyphomycetes, and as 

 including all those filamentous fungi which bear naked spores at 

 the apex of simple or branched threads. 



Instead of going to the woods for a second example, let us take 



