ACTION OF LIVING SPONGE. 259 



its natural character : it is but a tiny bit of mammil- 

 lary sponge, some inch and a half in diameter. Let 

 us then drop our comparison, and think of it as 

 what it is. 



Here, as in the former case, a strong intestine mo- 

 tion is visible in the water to the unassisted eye ; and 

 the lens quickly enables us to trace this to a powerful 

 and constant ejection from the mammillary orifices. 

 But it is far more forcible in this example than in the 

 other. In order to see it to advantage, we must rub 

 a little carmine on a palette, and with a cameFs-hair 

 pencil diffuse carefully a small portion of the fluid 

 pigment in the water of the cell, making it slightly 

 dimmed with pink clouds. Then lifting the cell upon 

 the stage of the microscope, but so cautiously as not 

 to give the least jar or shock to the contents, we must 

 apply a somewhat low power, about seventy or 

 eighty diameters, for instance, and anew watch the 

 result. 



It is beautiful now to see the process having been 

 performed so gently that the living action of the 

 Sponge has not for a moment been intermitted, how ' 

 the water, loaded with the atoms of red pigment, into 

 which the magnifying power is sufficient to resolve 

 the clouds, is uniformly drawn from all surrounding 

 parts within a certain range towards each orifice, 

 slowly and imperceptibly in the remoter parts of the 

 circle, but ever acquiring more and more velocity, till 

 it rolls up the sides of the hill, and then is shot away 

 perpendicularly like a torrent of smoke and ashes 



