58 SYMBIOSIS 



It is as though Nature had set her face sternly against a wide- 

 spread " lowering of the tone," against an " infection " of good 

 character by contact with bad, against the application of the 

 well-known principle Mains malum vult, ut sit sui similis. 



Here we have a case of plants, backward so far as symbiotic 

 relations with the animal world are concerned, whose protoplasm 

 is so poor in values that a union with that of man, for instance, 

 produces violent forms of antagonism and even acute disease. 

 In the absence of active Symbiosis between man and these plants, 

 the seeds of the latter act as poison to the protoplasm of man. 

 There is, it would seem, a clash between genuinely symbiotic 

 momenta upon which health normally depends and momenta 

 of a totally different, i.e., non-reciprocal order. 



From a very interesting article on the subject by Dr. W. 

 Scheppegrell, A.M., M.D., in the Scientific American, Supp. 

 No. 2iiq (12-8-16), we obtain the following data : 



The class of plants whose pollen may cause hay-fever are wind-pollin- 

 ated, that is, the process of fertilisation is effected by the pollen being 

 borne by the wind instead of this being done by contact or by insects. 

 This explains the presence of such pollen in the air. In some cases the 

 pollen is present in enormous quantities, as for instance in the rag-weeds, 

 in which it has been estimated that only one in a hundred million pollen 

 grains is actually used in fertilizing the pistillate flower. The plants that 

 are responsible for hay-fever are practically all common weeds, such as the 

 rag-weeds, cockle bur, yellow dock, etc., which are also a source of expense 

 and labour to the farmer. Their characteristics are as follows : They 

 are wind-pollinated, without attractive colour or fragrance, very numerous, 

 and with abundant pollen. The lack of colour or scent is due to the fact 

 that these plants are wind -pollinated, the qualities mentioned being 

 intended to attract insects for fertilization. 



I think it clearly emerges that the culprits are the waywards 

 amongst plants, those that have not been able to strike up a 

 useful symbiotic relation with man or beast. Not being able to 

 render themselves useful, they become impediments and veritable 

 pests. At the same time we see another illustration of the truth 

 that absence of a symbiotic relation renders possible or necessi- 

 tates enormous though often wasteful and inferior reproduction. 

 We have already inferred that such redundant rates of multipli- 

 cation are only too likely to be in inverse ratio to biological 

 utility and really connected with pathological conditions. Here 

 we have one pathological terminus more specially brought home 

 to us. We may say that the moderation and restraint incumbent 



