( lOl' ) 



NOTES AND CORRESPONDENCE. 



The Infusoria. — Great uncertainty still prevails with respect 

 to the internal organs of these forms, and from the details 

 recently published regarding them (chiefly abroad) , it appears 

 that a more intimate knowledge of their physiology tends to 

 show that, although not so highly organized as they were 

 represented by Ehrenberg, they are not so simple in their 

 internal structui'e as they were supposed to be by some later 

 observers. 



Under these circumstances, I may be allowed briefly to 

 submit the chief results of my observations during the past 

 twelve months, so far as they bear upon the subject under 

 consideration. 



AUinentarij vesicles. — Having repeatedly Avatched the in- 

 gestion of food, both with and without adding indigo to the 

 water in which the Infusoria were contained, I have fre- 

 quently observed — 1st. The alimentary particles, which are 

 driven in by the action of the oral cilia, and are accompanied 

 by more or less water, enter the gullet, accumulate just 

 beyond its termination within the body, and there form a 

 ball. This ball, as is well known, sinks into the body after 

 it has attained a certain size. 2d. That the globules or balls 

 thus formed appear fixed in Glaucoma, &c., and to rotate in 

 Nassula, &c., as mentioned in your number of last January. 

 But I would now add, that in the former types they also 

 move, but so slowly, that their motion is only perceived after 

 long and careful observation. 3d. Sometimes, when there 

 have been but few particles of indigo, I have seen the globule 

 formed by the admission of water, and ivithin that globule 

 small particles of indigo rotated rapidly so long as the 

 process ot formation continued; but as soon as the globule 

 sank into the body, the rotation ceased. This must not be 

 considered as a proof that the action of the oral cilia is 

 constant and mechanical ; for I have often seen Glaucoma 

 scintillans with its body as clear as crystal, and perfectly free 

 from food-globules or any vesicles, excepting the contractile 

 vesicle. The alimentary vesicles appear to get rid of their 

 contents gradually, the refuse passing through the anal 

 orifice, wherever that may be situated. 



Contractile vesicles. — Of the various theories that formerly 

 existed concerning these organs, two opposite ones still 



