18 CURREY, ON THE SPIRAL THREADS 



Nepenthes and the vessels of the Coniferae up to the perfect 

 spiral vessel, and afterwards the degeneration of the perfect 

 spiral vessel into the " worm-shaped bodies " (wurmfonlnge 

 korpen) in the tub-rs of the Orchideae and in other plants, 

 concluding with an expression of opinion that these spiral 

 fibrous-cells must be considered as imperfectly developed 

 forms of the spiral vessel.* 



Soon after the publication of Corda's observations, Mr. 

 Berkeley noticed the threads in question in the Annals of 

 Natural History, and stated that so far as he had investigated 

 them they differed in no respect from the spiral vessels of the 

 higher plants. 



The next observer was Schleiden, whose opinion was en- 

 th'ely opposed to the Jihrous theory of Corda and Berkeley. 

 He (Schleiden) says that he has reason to believe that no 

 spiral fibre exists, but that the threatls are flat band-like cells 

 spirally twisted, thus attributing the spiral appearance to the 

 existence of a twist in the cell-wall. Dr. Schacht in his ad- 

 mirable work, " Die Pflanzenzelle," subscribes to Schleiden's 

 opinion, and states that he was long ago convinced that no 

 spiral band exists, but that the appearance by which Corda 

 was deceived arises from the torsion of flat thread-like cells. 

 According to Schacht, Dr. Klotzsch found that in an early 

 stage of the threads no spiral appearance was visible. 



Mr. Henfrey in a late communication to the Linnaean Society 

 has given the result of his own observations, and expresses a 

 very confident opinion as to the existence of a spiral fibre ; so 

 much so that, having the greatest faith in the observing powers 

 of Schleiden and Schacht, he is driven to doubt the goodness 

 of their instruments. 



A careful examination of the threads of several species of 

 Trichia has led me to a conclusion different from those of the 

 observers above referred to ; and I will proceed to state the 

 objections which appear to me to exist against the theories of 

 Corda, Berkeley, and Henfrey on the one side, and of Schacht 

 and Schleiden on the other. There is no substantial difference 

 between the views of Corda and Berkeley, who agree in the 

 main point of the existence of a spiral fibre. In the first 

 place the non-existence of spiral vessels in other genera of 

 fungi t (Batarrea perhaps excepted) affords some prima facie 

 ground for supposing that the organisms in question do not 



* Corda's expression is, " Erstarrte Traumhilcl,'" meaning hterally, " a 

 vision become rifjid.^' 



t Bonorden, in his ' Handbuch der AUgemeinen Mycologie,' states, 

 that a spiral fibre exists in Arcyriapuvirca ; but this, I appieliend, is a 

 mistake. 



