NOTES AND MEMORANDA. 169 



Organization of Hygrocrocis arsenicus, Breb. — This cryptogam 

 was gathered for the first time in 1836, and presented to tlie ' Academie 

 des Sciences ' by Bory Saint- Vincent, who referred it to the genera 

 Hygrocrocis or Leptomitus, which de Brebisson confirmed by naming 

 it Hygrocrocis arsenicus. In 1841 Louyet foand it again in Belgium. 

 Since then, although all druggists might have seen it in their bottles 

 of arsenical preparations, it has not attracted any attention. 



M. L. Marchand has recently studied it as developed in " Fowler's 

 solution," and thus describes it:* — The invasion of the solution 

 commences as an opaline cloudiness in suspension in the liquid. 

 This cloudiness, examined under the Microscope, presents the appear- 

 ance of a glairy mass containing brilliant points, fine dust, whose 

 particles are so minute that they cannot be measured. 



Later on, the spot increases and becomes' coloured in the centre. 

 The periphery remains glair j, but the centre (the oldest part) shows 

 globules in tubes, whose walls, with age, become less xmdecided. 

 These tubes are ramified, and then their contents become homo- 

 geneous. In proportion to their age the formation of septa takes 

 place. The septa, at first widely separated, approach each other in 

 such a manner that the dimensions of the cells become equal in all 

 directions. 



At first the mass remains opaline and floating in the liquid if the 

 bottle has not been shaken; later on the cloudiness becomes dark 

 towards the centre, and at last presents a brownish point, which 

 increases and reaches the periphery ; the opaline portions are invaded, 

 and the mass, become brown, is precipitated at the bottom of the 

 bottle. Examined under a low power, it resembles a little chest- 

 nut from 1 to 3 mm. in diameter, bristling with points. These 

 points are the extremities of filaments, which for the most part 

 have become torulose, knobbed and irregular, and some moniliform. 

 From their protuberances start fresh filaments which ramify, or little 

 blisters, which are hyaline and pyriform. The mass becomes more 

 and more brown, and at last completely black ; the plant is now in 

 fructification. 



If the elements which compose it are examined at this stage we 

 find— 



1st. That the filaments of the periphery are elongated inordi- 

 nately into hyaline tubes, which terminate in a glairy mass, which 

 envelops the organism and forms a cloudiness round it which re- 

 sembles the cloudiness which first appeared; in this network and 

 glairy mass float spores, and the debris of various organs. 



2nd. That all the filaments of the centre have assumed new forms. 

 The torulose moniliform filaments have increased and become almost 

 entirely black. It is impossible henceforth to see their contents ; 

 they disarticulate with extreme facility, and the knobbed irregular 

 filaments disarticulate with the same facility. They are less dark in 

 colour, but the pyriform blisters which they have formed have become 

 sporangioles of a very dark hue, particularly on the side of the point 

 which attaches them to the filament ; at their opposite part, which is 

 * ' Comptes Reudus,' vol. Ixxxvii. (1878) p. 761. 



