82 Traces of Unity in Plants and Animals. 



Dionaea muscipula, and in certain other cases. Here, 

 indeed, are hollows in which an actual process of diges- 

 tion would seem to be carried on, for the plant is rightly 

 believed to feed on the insects drowned in the sac of the 

 pitcher-plant or captured and killed between the armed 

 leaves of the Dionaea muscipula. Nor is the possession 

 of viscera and visceral cavities an absolute peculiarity of 

 animal bodies. In the " placenta " and seed-chamber of 

 the fruit the ovary of animal bodies and the visceral 

 cavity in which it is lodged would seem to be copied 

 not inexactly ; and, after all, there is but little that is 

 really peculiar in any other of the visceral organs. The 

 most complex gland is developed from an original of 

 the simplest sort a simple follicle, which again has 

 much in common with a simple polype or a simple 

 ciliate-cell ; and the hollow, moveable, poison-fang of 

 the serpent which may be regarded either as a glan- 

 dular follicle with the lips prolonged into a formidable 

 weapon, or else as one of the many forms of limbs and 

 appendicular organs may be taken as one of many 

 bonds of connection between the ordinary internal 

 visceral organs on the one hand, and the ordinary ex- 

 ternal organs of the body on the other. 



And thus, in plant and animal alike, distinct traces 

 of unity are met with, not only in the primordial cell 

 which is the common starting point of development for 

 every part of this organism, and for the organism as a 

 whole, but also in the manner in which development is 

 carried out subsequently in every case. 



