50 The Science of Life. 



" Little more than thirty years ago", he says, " we knew prac- 

 tically nothing of the life-history of a fungus, nothing of parasit- 

 ism, of infectious diseases, or even of fermentation, and many 

 botanical ideas now familiar to most educated persons were as 

 yet unborn. Our knowledge of the physiology of nutrition was 

 in its infancy, even the significance of starches and sugars in the 

 green plant being as yet not understood; root-hairs and their 

 importance were hardly spoken of; words like hetercecism, sym- 

 biosis, mycorhiza, &c., did not exist, or the complex ideas they 

 now connote were not evolved. When we reflect on these facts, 

 and remember that bacteria were as yet merely curious 'animal- 

 culse', that rusts and smuts were generally supposed to be 

 emanations of diseased states, and that ' spontaneous genera- 

 tion' was a hydra not yet destroyed, we obtain some notion of 

 the condition of this subject about 1860." 



As Marshall Ward points out there were early workers 

 of great merit, such as Fries the Linnaeus of the Fungi; 

 the Tulasnes, who began the elucidation of intricate 

 life-histories, such as that of ergot; and Berkeley, who 

 "linked the period previous to 1860 with the present 

 epoch" but it was to the genius of De Bary that we owe 

 the first great steps towards an understanding of the 

 Fungi: 



" If I may compare a branch of science to an arm of the sea, 

 we may look upon De Bary's influence as that of a Triton rising 

 to a surface but little disturbed by currents and eddies. The 

 sudden upheaval of his genius set that sea rolling in huge waves, 

 the play of which is not yet exhausted. ... His development 

 of the meaning of sexuality in Fungi, his startling discovery of 

 hetercecism, his clear exposition of symbiosis, and even his 

 cautious and almost wondering whisper of chemotaxis were all 

 fruitful." 



With De Bary's name is also associated one of the 

 most remarkable botanical discoveries of the second half 

 of the nineteenth century, namely, that "Lichens are not 

 a class co-ordinating with the Algae and Fungi, but a 

 division of Ascomycete Fungi which have this peculiarity, 

 that they spin their threads round the plants on which 

 they feed and take them up into their tissue." In othei 

 words, lichens are dual plants, illustrating symbiosis 

 between fungoid and algoid partners. De Bary's sug- 



