160 FOOTNOTES FROM 



which occurs in these inhospitable regions, consisting as 

 it does of a modification of cellulose, without any delete- 

 rious mixture. It affords food and shelter to several 

 species of Podurae, and an interesting little spider called 

 Desoria Arctica. In the warm springs of India the 

 Nostoc frequently occurs, and is successfully employed 

 by the natives as an outward application for scrofulous 

 affections, owing to the presence in it of minute quan- 

 tities of an alkaline iodide. In China, it is a frequent 

 denizen of ponds and streams, whence it is carefully 

 gathered and dried, to form an ingredient with the 

 famous edible bird's nests, in their rich and nutritious 

 soups. In the salt lakes of Thibet, and the marshes in 

 the woods of New Zealand, it attains frequently gigantic 

 proportions, forming masses of quaking gelatine, many 

 feet in circumference. The vulgar suppose the Nostoc 

 to be the remains of a fallen star, or of a Will-of-the- 

 wisp, and hence they attach many superstitious ideas to 

 it. It derived its name from Paracelsus, the celebrated 

 alchemist, who employed it from its ambiguous character 

 and simple structure in the composition of the universal 

 solvent and the elixir vitse. We find frequent mention 

 of it in the writings of the alchemists, by whom it was 

 highly esteemed on account of the mysterious virtues 

 which it was supposed to possess. 



The structure of this plant, simple as it appears, is 

 very curious and interesting. Examined under the 

 microscope, it is found to consist of a number of slender 

 moniliform threads or necklaces of spores, invested with 

 a firm and copious gelatine, which originated at an 

 early stage from each individual thread, but has now 



