268 MAN --AN ADAPTIVE MECHANISM 



histologic changes in the brain, adrenals and liver; 

 and functional changes in the thyroid and adrenals 

 identical to the changes produced by muscular work, 

 emotion, infection, etc. 



Section of normal liver of cat. Section of liver of cat after injections 



of leucin. 



FIG. 64. EFFECT OF LEUCIN ON THE LIVER 'OF A CAT. 



Note the general disappearance of cytoplasm and of nuclei in B. 



(From photomicrographs, X 1640.) 



In order to test these points experimentally, we 

 gave to animals intravenous injections of amino acids 



