STRUCTURE. 193 



carrying on of the total life, each of them consists of co 

 operative parts: there is cooperation within cooperation. 



There is another general aspect under which structures 

 must be contemplated. They are divisible into the universal 

 and the particular those which are everywhere present 

 and those which occupy special places. The blood which a 

 scratch brings out shows us that the vascular system sends 

 branches into each spot. The sensation accompanying a 

 scratch proves that the nervous system, too, has there some 

 of its ultimate fibrils. Unobtrusive, and yet to be found at 

 every point, are the ducts of the lymphatic system. And in 

 all parts exists the connective tissue an inert tough sub 

 stance which, running through interspaces, wraps up and 

 binds together the other tissues. As is implied by this de 

 scription, these structures stand in contrast with local 

 structures. Here is a bone, there is a muscle, in this place 

 a gland, in that a sense-organ. Each has a limited extent 

 and a particular duty. But through every one of them ramify 

 branches of these universal structures. Every one of them 

 has its arteries and veins and capillaries, its nerves, its lym 

 phatics, its connective tissue. 



Recognition of this truth introduces what little has here 

 to be said concerning organs ; for of course in a work limited 

 to principles no detailed account of these can be entered 

 upon. ^This remainder truth is that, different as they may 

 be in the rest of their structures, all organs are alike in certain 

 of their structures. All are furnished with these appliances 

 for nutrition, depuration and excitation : they have all to be 

 sustained, all to be stimulated, all to be kept clean. It has 

 finally to be remarked that the general structures which 

 pervade all the special structures at the same time per 

 vade one another. The universal nervous system has every 

 where ramifying through it the universal vascular system 

 which feeds it; and the universal vascular system is fol 

 lowed throughout all its ramifications by special nerves 

 which control it. The lymphatics forming a drainage- 



