362 Anal;ysis of Scientific Books and Memoirs. 



the composition of Blanc-mange, as well as other dishes." From the pro- 

 portion of iodine likewise contained in many species of Algce, their use as 

 articles of the Materia Medica is introduced, we believe, with eflfect, in cases 

 where the prescription of that mineral is indicated. 



A work of the nature of Dr Greville's, is not susceptible of analysis ; we 

 shall therefore quote from his introduction some remarks regarding the 

 geographical distribution of the Marine Algos. ** To a considerable extent," 

 he observes, " they seem to obey the same laws as the higher orders of ve- 

 getable forms. But it is doubtful if we are at present acquainted with all 

 the agents which influence the growth of plants in a medium so diiferent 



from air as that of water. The distribution of the marine Algce engaged 



the attention of the late Professor Lamouroux, whose essay upon the sub- 

 ject was published posthumously, in the 7th vol. of the Annales des Scien- 

 ces Naturelles. M. Bory de St- Vincent has also added some observations, 

 but mixed up with a good deal of extraneous matter, in the botanical part 

 of Duperry's voyage round the world. 



"It is very clear, and well known to the practical botanist, that marine 

 plants are much influenced by the nature of the soil, not merely in regard 

 to species, but in luxuriance and rapidity of developement. A few yards 

 is in some instances sufficient to create a change, and the space of three or 

 four miles a very striking one. Thus calcareous rocks favour the produc- 

 tion of some species, sandstone and basalt that of others; and it would ap- 

 pear that the soil has an effect even upon those Algce which grow parasiti- 

 cally upon the stems of the larger species. But sometimes, to all appear- 

 ance independently of this cause, peculiar forms predominate in certain lo- 

 calities, both in regard to genera and species, which, as we approach their 

 boundaries, gradually disappear, and often give place to others equally 

 characteristic. 



" Phaenogamous plants have furnished botanists with several grand vege- 

 table regions, and a marked difference (not to specify more examples) has 

 been recognized between the plants of America, Africa, Asia, Australia, 

 and Europe. Lamouroux endeavoured to trace these great divisions among 

 marine plants, and observed that the polar Atlantic basin, to the 40th de- 

 gree of N. latitude, presents a well-marked vegetation. The same may be 

 said of the West Indian sea, including the gulf of Mexico — of the Eastern 

 coast of South America — of the Indian ocean and its gulfs, — and of the 

 shores of New Holland and the neighbouring islands. The Mediterranean 

 possesses a vegetation peculiar to itself, extending as far as the Black Sea, 

 and notwithstanding the geographical proximity of the port of Alexandria 

 and the coasts of Syria to these of Suez and the Red Sea, the marine plants 

 of the former, in regard to species, differ almost entirely from those of the 

 latter. Bory de St- Vincent characterizes each of his Mediterranean seas 

 by a vegetation different from that of the Arctic, Atlantic, Antarctic, In- 

 dian and Pacific oceans, and, to a certain extent, he is probably correct, as 

 such seas are of less depth, often of a higher temperature, and more direc- 

 ly influenced by the countries which more or less inclose them. The seas 

 which he considers as Mediterranean, are the Mediterranean, properly so 

 called, the Baltic Sea, the Red Sea, the Persian Gulf, the Chinese Sea, the 



