ON THE NOTOCHORD 251 



and function, although a matter of altogether vegetable 

 bearing, we cannot forbear calling attention to the pith of 

 plants, a ligneous element, which seems to perform in the 

 process of plant life and growth, a very similar function 

 to that of the notochord in animal embryonic life, convey- 

 ing to the distal buds from the earth, we think, the 

 inorganic, or earthy, salts, and other materials, for the 

 solidification of ligneous tissue, while the more aqueous, 

 and organic are conveyed up the exterior in the sap 

 proper. Of course the pith of plants is a permanent, 

 and not an ephemeral structure, and continues annually^ 

 or perennially^ to perform its vital functions of circulation 

 and lignification. 



We seem here, in embryonic life, to be face to face 

 with problems, involving the conjoint action, of both the 

 sympathetic, and systemic, nervatures, not only on their 

 material aspects, but on their dynamic ; so that we have 

 the play, in the accomplishment of the phenomena referred 

 to, of four factors, two material, and two dynamic, viz. 

 the sympathetic, material, and dynamic, neuro-circulatory, 

 each of which is called upon to act individually, and 

 communally, for the accomplishment of common organic 

 objects. Necessarily, therefore, the partnership working 

 out of the problems in question entails very complicated 

 methods, of formative, and reparative, procedure, but 

 when the physiological compact is capable of straight- 

 forward accomplishment, the various factors, mutually, 

 and spontaneously, assist each other, so that finally, what 

 had seemed an impossible work, is accomplished with the 

 utmost, ease and precision. 



Thus, the material lines having been determined upon, 

 and laid down, the dynamic factors lick into shape the 

 mutual material contributions of the two systems, and 

 evolve organic order, out of what may have appeared 

 chaos, as when in the case of bone fracture, callus has 

 been contributed from all sources in the scene of the 

 traumatic area it becomes necessary, for the accomplish- 

 ment of the one object, of attaining the condition of the 

 status quo ante, for both systems to put forth their accu- 

 rately guided dynamic efforts, for the common purpose of 

 securing a physiological, and avoiding a pathological result. 



