The purpose of this paper is to illustrate the advantages of the 
chemo-morphological approach in the study of pathological material. On one hand, 
the analysis of selected pathological cases (amputations, spinal transections) 
is able to provide invaluable information concerning the cells of origin of 
certain spinal transmitters in the human being. On the other hand, chemical 
neuropathology allows a more precise identification of the neuronal nets or 
types that are involved in a disease process. This advantage is underlined by 
studies performed in amyotrophic lateral sclerosis. In this condition, certain 
modifications, such as the reductions of acetylcholinesterase, choline 
acetyltransferase, cholinergic muscarinic, glycine or TRH receptors, are 
probably a consequence of motoneuron degeneration. In contradistinction, other 
findings, such as specific metabolic changes of motoneurons or early 
disappearance of SP-containing fibers in lamina IX, might be relevant for the 
pathogenesis of the disease.