100 GENERAL ANALYSIS. 



not vary the simple plan of the Blood-circuit ; it may 

 also be mentioned that the eliminating or supplying or- 

 gans may be attached to either the arteries or veins, or 

 a part of them to each, without essentially varying the 

 simple plan. 



366. IF THE FORCES THAT MOVE THE BLOOD THROUGH 

 A SINGLE CIRCUIT DO NOT SUFFICE tO mOVC it thl'OUgh 



an eliminating organ with sufficient rapidity, another 

 Heart must be introduced, and the veins which lead the 

 Blood back must open into that H'eart, from which an- 

 other set of arteries must arise and lead to a set of 

 capillaries in the eliminating organ, from which veins 

 must lead to the first heart, as follows : 



2d, 1st, 1st, 



2d ^ Veins, HEART, ARTERIES, 1st f 



Capillaries, * CAPILLARIES, 



i< < < (K I 



Arteries, Heart, VEINS, y 



2d, 2d, 1st, 



367. THE TWO HEARTS AND THEIR CONNECTIONS ARE 

 SPOKEN OF as forming a double circulation, called the 

 greater or systemic, and the lesser respiratory or pulmo- 

 nary circulation, when in fact all the parts constitute 

 but a single circulation, and the greater should be called 

 the greater part of the circulation, and the smaller the 

 smaller part, etc. It is no longer a simple but a com- 

 pound circulation. 



368. THE TWO HEARTS SHOULD BE LOCATED by the 

 side of each other, and enclosed within the same external 

 covering; therefore externally they appear to be one 

 thing, and are, in fact, so called, viz., the Heart. For 

 the purpose of close packing, the tubes or vessels leading 

 into and out of them are so intertwined that great com- 

 plexity at first appears, where, in fact, there is great 

 simplicity. (See pi. 5 and 27.) 



866. What ? Write and describe table. 867. How ? 868. How? 

 tbere complexity or simplicity in arrangement of Blood-tubes ? 



