154 On the Red Coloring Matter of the [No. 9, new series. 



sides red, spots of white, yellow, green, and brown water have 

 been seen in different parts of the Globe, but those of red and 

 white are most common in the Arabian and Red Seas, and of 

 these two the red will chiefly occupy us here. They are of tran- 

 sitory duration, and so far as the latter or red color is concerned, 

 receive explanation from what occurs at our own doors, viz., in 

 the sea-water pools left by the reflux of the tide on the shores of 

 the Island of Bombay. A person casually looking at one of these 

 pools would say that a quantity of vermillion had been thrown 

 into it, but on examining the water under a microscope the color 

 is seen to be owing to the presence of red animalcules whose 

 name is Peridinium. These are not all red however, for there are 

 many green ones among them, and the former are further observed 

 to be but a transitional state of the latter. This then is the cause 

 of the red color, and its sudden appearance and disappearance 

 may be explained as follows : — 



During the first or active part of the Peridinium? s life, its green 

 color, which depends upon the presence of a substance closely al- 

 lied to, if not identical with, the chlorophyll of plants, is, with the 

 other internal contents, translucent, and, therefore, reflects little 

 or no light ; but gradually, as the time approaches for its transi- 

 tion to another state called the motionless, fixed or protococcus 

 form, a number of semi-translucent, refractive oil-globules are se- 

 creted in its interior direct or through transition from starch ; the 

 green color disappears, a bright red takes its place ; this mixes 

 with the oil, and thus the little animalcule finally becomes visible 

 to the naked eye, and the whole of that portion of the sea charged 

 with them, of course, of a deep vermillion color. This color, how- 

 ever, only lasts for a few days, for they soon assemble together, 

 become individually capsuled, and in this state smk to the bottom 

 in the motionless or protococcus form mentioned. Here dupli- 

 cative subdivision takes place in several of the capsules, produc- 

 ing two or four new ones from the old Peridinium, each of which, 

 on their liberation, may again become capsuled and undergo a fur- 

 ther division, and so on probably until their formative force is ex- 

 pended, and they thus pass into dissolution ; or a litter of diplo- 

 ciliated monads may be developed in their interior, which may be 



