YEAST. 585 



plasm of the nettle-hair. That account was drawn up from careful and 

 often-repeated observation of the facts. Dr. Stirling thinks he is offer- 

 ing a valid criticism, when he says that my valued friend Prof. Strieker 

 gives a somewhat different statement about protoplasm. But why in 

 the world did not this distinguished Hegelian look at a nettle-hair for 

 himself, before venturing to speak about the matter at all? Why 

 trouble himself about what either Strieker or I say, when any tyro can 

 see the facts for himself, if he is provided with those not rare articles, 

 a nettle and a microscope? But I suppose this would have been 

 "Avfkliirung " a recurrence to the base, common-sense philosophy of 

 the eighteenth century, which liked to see before it believed, and to 

 understand before it criticised. Dr. Stirling . winds up his paper with 

 the following paragraph : 



In short, the whole position of Mr. Huxley, (1) that all organisms consist 

 alike of the same life-matter, (2) which life-matter is, for its part, due only to 

 chemistry, must be pronounced untenable nor less untenable (3) the material- 

 ism he would found on it. 



The paragraph contains three distinct assertions concerning my 

 views, and just the same number of utter misrepresentations of them. 

 That which I have numbered (1) turns on the ambiguity of the word 

 " same," for a discussion of which I would refer Dr. Stirling to a great 

 hero of "Aufklarung" Archbishop Whately; statement number (2) 

 is, in my judgment, absurd; and certainly I have never said any 

 thing resembling it ; while, as to number (3), one great object of my 

 essay was to show that what is called " materialism" has no sound 

 philosophical basis ! 



As we have seen, the study of yeast has led investigators face to 

 face with problems of immense interest in pure chemistry, and in ani- 

 mal and vegetable morphology. Its physiology is not less rich in sub- 

 jects for inquiry. Take, for example, the singular fact that yeast will 

 increase indefinitely when grown in the dark, in water containing only 

 tartrate of ammonia, a small percentage of mineral salts, and sugar. 

 Out of these materials the Torulce will manufacture nitrogenous proto- 

 plasm, cellulose, and fatty matters, in any quantity, although they are 

 wholly deprived of those rays of the sun, the influence of which is 

 essential to the growth of ordinary plants. There has been a great 

 deal of speculation lately, as to how the living organisms buried beneath . 

 two or three thousand fathoms of water, and therefore in all probability 

 almost deprived of light, live. If any of them possess the same powers 

 as yeast (and the same capacity for living without light is exhibited by 

 some other fungi), there would seem to be no difficulty about the 

 matter. 



Of the pathological bearings of the study of yeast, and other such 

 organisms, I have spoken elsewhere. It is certain that, in some ani- 

 mals, devastating epidemics are caused by fungi of low order similar 



