388 PHYSIOLOGY, CHEMISTRY, AND MORPHOLOGY. 



the organism, for the nutritive necessities of life, for the testhetic exi- 

 gencies of sex. In all this chemistry has an immense field of fraittul 

 research before it, and we sliall fln<l in the phenomena of living beings 

 the desired instructions for making life easier, for improving and defend 

 ing it, for rendering it sufficiently productive to permit us to practice 

 that .social altruism that nature herself now prevents us from attaining. 

 But this field is now and will remain more practical than theoretical, 

 more utilitarian than scientific, because, even if the complicated i)roc- 

 esses going on within the crucibles of life were well kuown to all, life 

 itself would always remain for us unknown and impenetrable. IJut 

 this ought not to deter us; we shall keej) on trying and testing, accu- 

 mulating facts, pushing as far as possible our analytical researches, 

 convinced that we should be content to seek truth without accjuiriug 

 the whole of it. 



As you see, we are to-day already quite far from the systems in vogue 

 a few years ago, and, knowing more, we realize more clearly how slight 

 is the scope of our knowledge; for with increased knowledge comes an 

 enlargement of our conception of the complexity of the plienomena of 

 life; the horizon of the unknown widens out in vast relative proj)or- 

 tions. For this reason permit me to believe that the moment is not 

 yet at hand when the facts developed Avithin the living organism can 

 receive an astronomic sanction, and let me recall to you what was said 

 by Giiiileo, the founder of the experimental method, the regenerator 

 of imtural philosophy: "I have always held him extremely rash who 

 attempts to njeasure by human capacity all that nature can and will 

 do, since there is not, on the contrary, a single effect in nature, how- 

 ever small it may be, that can be entirely understood by the most pen- 

 etrating intelligence. This idle presumption of wishing to understand 

 everything must necessarily arise from never having understood any- 

 thing; for if he had ever applied Jiimself to perfectly understand any 

 one thing, and had really apineciated what constitutes knowledge, he 

 would know that in the infinity of other conclusions he does not under- 

 stand one."^ 



We ought, wiien experimenting, to always have these words in mind; 

 for if it Is true that we ought to keep our attention firmly fixed upon a 

 fact until we have ac(iuired a clear and limpid i»erception of it, it is 

 none the less so that before interi)reting it we ought to consider its 

 entire surroundings, remembering that it is not isolated, but, on the con- 

 trary, a simple facet, infinitely small, of a preeminently complex whole. 

 Let us not imitate the presum])tuous physiologists that achieve success 

 by the apparent clearness of their explanations, giving the ])upil the 

 agreeable illusion that he can learn much, quickly, and without fatigue. 

 This, unfortunately, is a too general tendency, and we often see how, in 

 their desire to warp the phenomena of life to the limits of their own 



1 Galileo (Galilei). Dialogo del dur massimi sistemi del mondo, Firenze, 1842, vol. 

 1, page 114. 



