1910.] Blood in Vertehrates and Invertebi-ates. 



603 



author,* unaware of the speculations of Bunge and Quiuton, advanced the 

 view that the blood plasma of Vertebrates and Invertebrates with a closed 

 circulatory system is, in its inorganic salts, but a reproduction of the sea water 

 of the remote geological period in which the prototypic representatives of 

 such animal forms first made their appearance. It was pointed out that in 

 many Invertebrates with a vascular system still freely communicating with 

 the exterior, the circulatory fluid is sea water, and this was probably the 

 case also with ancient oceanic forms. The tissues in these latter had through 

 a long period of time become so accommodated to the composition of the sea 

 water of the period that when the circulatory system acquired the closed 

 condition, the composition of the sea water of that period was, with slight 

 modifications, reproduced in the vascular fluid, and thus transmitted to the 

 descendant forms living in different habitats. 



As corroborative of this view it was shown that even between the inorganic 

 composition of the blood serum of mammals and that of the ocean of to-day 

 there is a striking resemblance. This is not in concentration, for the saUnity 

 of the ocean is about three times that of mammalian blood serum, but in the 

 relative proportions of the sodium, potassium, and calcium, as indicated 

 thus : — 





Na. 



K. 



Ca. 



Mg. 





100 



6-69 



2-58 



0-8 





100 



3-66 



3«4 



11 -99 



The resemblances are very close except in the magnesium, but this 

 exception and the minor differences were explained as due to the alteration 

 in composition which the ocean has undergone since the Protovertebrate form 

 arose, for not only has there been an increase in the saline concentration 

 of ocean water, but there has obtained a change in the proportions of the 

 basic constituents. This has been brought about by the continual elimina- 

 tion of the potassium and calcium, and the retention of the sodium and 

 magnesium derived from the river discharge from the land areas of the 

 globe. 



In a subsequent communicationt these observations were amplified, and 

 evidence was advanced to show that the history of the composition of the 



* " On the Inorganic Composition of the Medusa?, Aurelia fiavidvla and Cyanea Arctica," 

 ' Journ. of Physiol.,' 1903, vol. 29, p. 213. 



t " The Palseochemistry of the Ocean in Relation to Animal and Vegetable Proto- 

 plasm," ' Canadian Institute, Transactions,' 1904, vol. 7, p. 535. 



