I 



I 



H. '[\ (iii88ow 157 



to the mother spore the '"handle of the duiiib-beH"' elongated somewhat, 

 and the secondary spore also appeared surrounded by a plasmatic 

 substance — just as did the mother spore — but in very much smaller 

 quantity. 



Immediately after the secondary spore was formed, it actually 

 did germinate. It should have been said that in the mother cell the 

 "exdentation"' occurred on almost any position of the spherical bcdy. 

 But with the secondary spore, germination, as opposed to the "exden- 

 tation" of the mother cell, took place at the end towards the mother 

 cell. Indeed what appeared at first as a rather long "handle to the 

 dumb-bell" was later recognised as a mycelial thread, or, more correctly, 

 tube growing into the cavity of the old spore. Naturally in many cases 

 the secondary spore often separated from the mother spore. 



The germ tube was seen to branch, and the contents of the spore 

 to be slowly used up, while the mycelium grew in size. This jsroduced 

 sparse, short, stout branches at no special points. Later on a second 

 germ tube grew from the secondary spore body ; on rare occasions 

 there were three in all. The growth made slow progress thereafter, 

 becoming detached from its spore shell, and assuming shapes and sizes 

 similar to the mycelial portion observed in the fat body ot the fly. We 

 have not been able to see a true tertiary spore in Emjpusa Muscae after 

 germination took place, although peculiar club or flask shapes occasion- 

 ally appeared which resembled spores ; but they could not, on examina- 

 tion, be determined as such. 



The growth remained pure all the time and made progress for 

 28 days on this medium. Then signs of disintegration appeared, and 

 the mycelium became vacuoled more and more, less sharp in outline, 

 and later collapsed. This is, so far as I knoAv, the longest time a 

 growth has been maintained outside a fly; but we cannot regard it 

 as a successful culture yet. Every effort to continue growth failed, 

 no doubt because it normally takes place in nature in the living fly 

 body. 



These observations clearly show that Mr Hesse's Mucor mcemosus 

 was nothing else but an impurity, and polymorphism does not occur 

 in this fungus, as represented at one time by Mucor and another by 

 Emjjusa. 



Every other experiment to continue the development of these 

 spores has failed so far. The absence of nutrients accounts for this ; 

 for the various ingredients tried to furnish material for continued 

 growth did not suit the fungus. The main points, from a scientific 



.\nn. Biol, m 11 



