of Minburgh, Session 1879-SO. xiii 



2, The following plants were on the table in bloom from the 

 forcing department of the Eoyal Botanic Garden : — Anigosantlius 

 breviflorus, raised from seed sent by Surgeon-Major Fleming from 

 Natal, where this Amaryllidaceous plant proved poisonous to horses 

 of Her J\lajesty's troops ; an Iberis from mountains above Crasse, 

 obtained from G. Maw, Esq.; an Enjt.hronium Nuttallianum; and 

 a new variety of seedling from Primula ciliata, which it is proposed 

 to designate P. ciliata var. Balfour iana. 



Thursday, loth May 1880.— Mr William Gokrie, 

 President, iu the Chair. 



The deaths of Miss Frances Hope, a Lady Associate, and of 

 Professor jST. I. Andersson of Stockholm, a Foreign Member of the 

 Society, were noted. 



The following Communications were read : — 



I. Microscopic Demonstration of the Fungus (Saprolegnia ferax) 

 of the Salmon Disease. By Mr A. B. Stirling, Assistant 

 Curator of Anatomical Museum, University of Edin- 

 burgh. Communicated by Professor Dickson. 



Several of the suite of specimens lately presented by Mr Stirling 

 to the museum of the Eoyal Botanic Garden, and including pre- 

 parations from the fish sent for exhibition to the January meeting 

 by jVIr G. Muirhead of Paxtou, Berwick-on-Tweed, were exhibited 

 under the microscope. The mode of propagation of this Sajjrolegnia, 

 and the way in which Mr Stirling holds that it destroys salmon 

 and other fresh water fish in our rivers, were demonstrated. Pro- 

 fessor Dickson, in explanation, said that the saprolegniae were 

 closely aDied in their general structure to such algae as Vaucheria. 

 They consisted, like Vaiccheria, of branching filaments, which, 

 however, were continuously tubular, differing in that respect from 

 the articulated filaments which occurred usually in fungi. Like 

 Vaucheria, Saprolegnia was reproduced both sexually and non- 

 sexually, in the latter process by Zoospores, which, when set free, 

 were capable of moving in the surrounding water. These Zoospores 

 were produced in enormous numbers, and must tend widely to 

 disseminate the species. 



