COMPENDIUM. 281 



But now its necessity, or its desire for replenishment, is more conspi- 

 cuously demonstrated than what is shewn by either the hydraoids or 

 asteroids above described. This is so evident as to preclude the chance 

 of error. Thousands eagerly absorb the muddy solutions prepared for 

 them until they can contain no more. 



As this is both artificially and forcibly done, it is easy to understand 

 how living animalcula may be accidentally absorbed with other substances 

 of the mixture. These may be retained, indeed, and possibly they may 

 be digested, which is nevertheless more doubtful. Here, however, I appre- 

 hend, is the explanation of what is said by some naturalists in expressing 

 their opinion that the ascidian hydra; are carnivorous. 



Excepting with regard to those notoriously and voraciously carnivo- 

 rous, my own observations on the food of zoophytes, farther than the ready 

 and copious absorption of muddy matter, have not been decisive. Ani- 

 mals, it is well known, may be sometimes reconciled to food which seems 

 unnatural. It is alike known that there are some, especially among the 

 smaller tribes, which not even the pressure of hunger can induce to taste 

 of substances unless of their own selection and preference. 



I acknowledge that I have been often much perplexed to account for 

 the rapid increment of zoophytes, when unable to detect the means of 

 their sustenance ; for it is not reasonable to admit that living bodies can 

 be enlarged, while preserving health and vigour, under continued abstinence. 



A certain waste seems to accompany the mere subsistence of life, 

 which the Great Architect of Nature has wisely made a provision to com- 

 pensate, by the desire of every perfect animated being for food, whence 

 are cavities in the animal frame also provided for its reception. 



A certain portion of the food must be, therefore, incorporated with 

 the system. 



6. Senses. — The senses of the whole race of zoophytes are apparently 

 very few, and their operation, for the most part, very obtuse and confined 

 in many. 



This is a subject, indeed, whereon we would do well to speak cau- 

 tiously, for we can judge of a sense in other beings than ourselves, only 

 vol. n. 2 N 



