306 Melamorphoses of the 



Among the naturalists who have laboured in this new and 

 singular field, Professor Nees von Esenbeck must be placed 

 foremost on the list, as he was the first to publish his observ- 

 ations, in a distinct manner, in the year 1814. Since that 

 period, Treviranus, Ditmar, Agardh, Bory de Saint- Vin- 

 cent, Gruithuisen, Carus, Gaillon, Desmazieres, and others, 

 have endeavoured to substantiate the truth of the pheno- 

 menon. 



The tribe of Oscillatoriae, forming a part of Agardh's great 

 group of Confervoideae, or jointed ^'Igae, are well known to 

 have derived their name from the oscillating motion of the 

 filaments. Nothing is more easy than to perceive this motion, 

 and the Oscillatoriae, consequently, are held in a dubious 

 point of view by all botanists. M. Vaucher, of Geneva, who 

 published a Histoire des Confer^ves d^eau douce, noticed such a 

 difference between the two extremities of the filaments in some 

 species, that he denominates one the head, and the other the 

 tail. 



Professor Agardh, of Lund, who has directed his attention 

 chiefly to the A'lgse, published, a few years ago, an ingenious 

 essay upon the metamorphoses of many species. To show how 

 far he has carried his observations, it will be sufficient to men- 

 tion that, in his I'cones Algdrum ineditce, fasc. 1. 1. 10., he has 

 represented the vegetable form of Oscillatoria flexuosa, and 

 also the animalcules into which the filaments are at length 

 converted. 



There can be no doubt, that the colouring matter of the 

 famous red snow (named Protococcus nivalis by Agardh), 

 brought from the arctic regions by Captain Ross and Captain 

 Parry, is a true vegetable, belonging to the order ^'Igse. It 

 grows upon limestone rocks, tufts of moss, dead leaves, and 

 even on the bare soil. The singularity of the situation, how- 

 ever, in which it was first discovered, that of pure snow, gave 

 rise to speculations regarding its origin. Professor Nees von 

 Esenbeck was inclined to think that the minute red globules, 

 of which the plant consists, were the vegetable state of bodies 

 which had gone through a prior animal existence, and perhaps 

 of atmospheric origin. 



Baron Wrangel, who discovered the Protococcus nivalis 

 growing upon limestone (without knowing at the time that it 

 was the true red snow), studied it very carefully. He men- 

 tions that the red crust was soon detached when placed under 

 water, and a number of much smaller globules, of a yellow or 

 pale colour, made their appearance, of which the larger red 

 globules seemed to be composed. After a lapse of three days 

 the globules became animated, like infusory animalcules ; they 



