158 COHN, ON EMPUSA MUSCLE. 



chemical and optical relations of the innumerable, free cells 

 in the blood-fluid, the absence of any special, self- extending 

 mycelium, and especially the entire history of the develop- 

 ment, appear to favour the notion of the origination of the 

 Empusa-cells in a free cell-development in the morbidly 

 altered blood. 



19. This disease of the fly, so far as at present known, 

 finds its only analogue in the epidemic disease of the silk- 

 worm termed " Muscardine," which has been ascribed to an 

 entirely different /mw^wj? — Botrytis Bassiana. 



20. But until the " Muscardine" shall have been subjected 

 to renewed and thorough investigation, no accurate judgment 

 can be arrived at with respect to the relation of the two dis- 

 eases to each other, a few observations rendering it doubtful 

 whether the Botrytis Bassiana, or, more probably, a fungus 

 allied to the Empusa musca, may not play the principal part 

 in this disease. 



The above account of Empusa muscae, the author observes, 

 was in print before the appearance of M. Tuslasne's 

 Memoire sur les Uredinees et les Ustilaginees' ('Ann. d. 

 Scien. Nat.,' 4 ser., tom. ii, pp. 77 — 193, 1854) ; in which 

 paper an account is given of the development of numerous 

 "smut-fungi," which diifers from all that was previously known 

 with respect to the development of these microscopic organ- 

 isms, and which, moreover, would seem calculated to throw a 

 new light upon the origin of certain morbid phenomena. 



In the germination of this class of fungi, for instance, the 

 peculiar, uni- or multi-cellular hypnospores, containing much 

 oily matter, and having a double membrane, are not at once 

 and directly developed into a new mycelium, but the endo- 

 sporium breaks through the outer membrane [cuticula] of the 

 spore and elongates into a short tube, which in length but 

 slightly exceeds the spore ; this germinal tube, tube-germe, pro- 

 mycelium (which would appear to correspond with the pi'o- 

 thallium of Mosses or the pro-embryo of Ferns), then bears a 

 considerable number of secondary sporidia, — in the " smut" of 

 wheat {Tilletia caries) 8 — 10 in number, — of a long-fusiform, 

 fusidium-\\ke shape, united in pairs by a transverse band, and 

 consequently altogether dissimilar to the peculiar, primary 

 spore. These sporidia soon detach themselves from the 

 germinal tube, whose entire protoplasm was employed in 

 their formation. These secondary spores even do not usually 

 appear directly to throw out a mycelium,, but first become 

 elongated into peduncles, supporting at the summit rcniform 

 cells — tertiary sporidia. At present it has not been observed 



