LIFE AND HABIT 115 



benefit. But it must be borne in mind that similar inter- 

 connectedness has always been the law of their being, and that 

 their special inter-connectedness, therefore, is by no means so 

 casual a matter as at first glance it looks. The special case of 

 the mistletoe merely consists in this : that we have here a partial 

 loss of the symbiotic sense, a retrogression from an erstwhile 

 purely symbiotic relation, inasmuch as the plant draws non- 

 reciprocally on another organism, namely the tree. The mistle- 

 toe presents an instance of a striking concomitance of a parasitic 

 with a symbiotic relation and of corresponding anomalies of 

 structure. It is this concomitance which introduces the com- 

 plexity and which is responsible for the difficulties of interpreta- 

 tion which baffled Darwin and many others. 



In the case of bio-economic retrogression, a kind of imbrioglio 

 is sure to arise in the constitution of the organism. The com- 

 ponents introduced by degenerative tendencies become variously 

 blended with, and superposed upon, the components of health. 

 The result may be a very heterogeneous mixture, a condominium 

 of components good and bad, ancient and modern. It may be 

 said that the very capacity for progress acquired painfully during 

 millenniums of symbiotic evolution, may come to be employed 

 by the organism retrogressively in accordance with a lazy 

 compliance with low conditions rather than in accordance with 

 progressive efforts. I consider the case of the mistletoe to be one 

 of this kind a case of partly disintegrated symbiotic integrity. 

 The mistletoe has by no means descended to the depth of a rank 

 parasite. The fact of the green colouration of its leaves alone 

 shows that this plant is not entirely devoid of wholesome bio- 

 economic activities. How are Biologists to distinguish what 

 is due to Symbiosis in an organism from what is due to parasitic 

 influences ? The reading of the respective symptoms will be 

 done by each according to his abilities of diagnosing Health and 

 Disease, according to the distinctions he is wont to draw as regards 

 values generally. So long as in the absence of agreement as to 

 " values," we have no definite biological analysis, the case of the 

 mistletoe of course, must remain perplexing. 



The need of tackling anew the problem of Variation in this 

 connection, has caused Butler to expand his " Mnemo-Lamarck- 

 ism " into an interpretation more specifically sociological, and 

 hence more satisfactory, than his previous view to the effect 

 that the saying that "what is one man's meat is another man's 



