6j\. botanical gazette. [ March, 



As a single nucleus has sufficed for fecundation, it is clear 

 that, on the basis of pangenesis, this must have contained 

 pangens, representing all hereditary characters belonging to 

 the father-plant. But all organs of the hybrid are hybridized 

 (plastids, vacuoles, etc.), and hence it follows that the hy- 

 brid nucleus can influence in some manner all other organs 

 of its protoplast, and thus all hereditary characters of the 

 species. 



Now the question remains, how it is possible that the nu- 

 cleus exercises such an influence. Various answers can be 

 given. Some authors maintain that a certain dynamic in- 

 fluence is transmitted from the nucleus to all other parts of 

 the living protoplast ; others propose the doctrine that cer- 

 tain enzymatic substances emanate from the nucleus and 

 can produce changes in the surrounding protoplasm. On 

 both these suppositions (and if it be conceded that the nucleus 

 contains all sorts of pangens) it must be assumed that in all 

 other organs of the protoplast there are peculiar substances, 

 capable of growth and propagation, and producing through 

 the dynamic or enzymatic influence from the nucleus those 

 visible effects of which the pangens are the representatives 

 For, as has been shown, tonoplasts, plastids, etc., can prop- 

 agate their kind, and it is through the activity of these 

 organs of the protoplasts that hereditarv characters become 

 manifest It is obvious that here is a secondary hypothesis 

 of which there is no need. For if it is assumed, with 

 Darwin, that not only the nucleus, but all other organs of 

 the protoplast, in short living protoplasm in the widest 

 sense of the word, consists of pangens, and of these only, 

 the hypothesis of two kinds of self-propagating particles, 

 corresponding with hereditary characters, becomes gratui- 

 tous. And at the same time, the supposition of a dynamic 

 or enzymatic influence, issuing from the nucleus, can on 

 this view be dismissed, whilst in its place comes the much 

 simpler suggestion that pangens can migrate from the nu- 

 cleus to all other organs of the same protoplast, of which it 

 torms the center. 



Our present views on the origin of species independently 

 lead to the same conclusion, as it is clear that in the first or- 

 ganisms without nucleus, pangens were diffused throughout 

 the whole protoplast, and were afterwards combined in one 

 body when a nucleus made its appearance. 



The hypothesis, explained in the foregoing lines is called 

 by Prof, de Vries that of « intracellular Vnge„e?i" Giv- 



