Pancreatic Glands ? of the Infusoria, 53 



visible ones in the body, and only in two instances, out of more 

 than a hundred, have they been found colourless. 



Regarding the Nassula ornata, and the Bursaria vernalis, 

 which are the other two species which frequently secrete this fluid 

 in great abundance, the Professor has not succeeded in discover- 

 ing any fixed points in which the secretion was effected. This, 

 perhaps, has arisen from the secretory organs of this fluid so much 

 resembling in form, size and situation, the other internal organs 

 of the animal, that they could not be discovered. In the A^a*- 

 sula ornaia, the secretion of this liquid is especially abundant, 

 more abundant even than in the Nassula elegans : in it the vio- 

 let vesicles are very clearly distinguished from the stomach, 

 which is filled with greenish or brownish-yellow matter, and 

 they are equally distinguished from the ova, which are of a 

 bright green colour. In the Bursaria vernalis its secretion is 

 much less abundant. It is perceived only at the time when the 

 water in which these little animals swim is evaporated, and when 

 their bodies, being no longer supported, swell ; or when a slight 

 pressure is applied to their frames without crushing them. When 

 treated in either of these methods, isolated stomachs or vesicles 

 may be discovered, which are filled with fragments of oscilla- 

 tores, or of vacillaires, and these surrounded with a violet, red- 

 dish or brownish liquid. 



M. Ehrenberg has remarked, that this violet liquid, which is 

 somewhat viscid, and almost oily, possesses a dissolving power, 

 which it exerts over all the bodies which it envelopes; for he has 

 often noticed, that in the stomachs which contained much of it, 

 the minute fragments of the oscillatores were always found 

 much altered and discoloured, divided or decomposed. He 

 also mentions another property which he had remarked. In 

 bruising one of these Nassulas, he has observed, that this beau- 

 tiful violet colour immediately disappeared as soon as it came 

 into contact with water, although the oily drop which it formed 

 did not mix with the surrounding mass. It was evident, then, 

 that the water exerted a chemical agency over the liquid. This 

 experiment was often repeated, and was witnessed by many, antl 

 the decoloration was always effected in the same way. Thai 

 more certainty might be obtained regarding this phenomenon^ 

 many of these animals were placed in small globules of oil, and 



