66 PHYSIOLOGICAL ROLE OF MINERAL NUTRIENTS. 



mammalia is therefore strictly in accord with the writer's view. There 

 is in 1,000 parts of fresh muscle of the — 



Part calcium. 



Frog 0. 1566 



Shad 2206 



Eel „ 3913 



or an average of 0.2562 part calcium. 



The importance of lime for the division of cells even in the lower 

 animal organisms is shown by Herbst's statement a that the most 

 important salt for the development of the sea urchin's eggs is calcium 

 phosphate, in the absence of which not even the completion of segmen- 

 tation is possible. The calcium of this salt is just as important as the 

 phosphoric acid. 



A relative increase of magnesia can be observed in organs in which 

 the nuclear mass is small. Thus the human brain contains more 

 magnesium than calcium, 5 and the muscles of mammalia contain in 

 most cases more mag'nesia than those of batrachia and fishes, as shown 

 bj^ Katz's results. 



There is in 1,000 parts of fresh muscl3 of the — 



Part 

 magnesium. 



Dog .0. 2370 



Hog 2823 



Deer . 2906 



Cat 2863 



Man 2116 



Average 2611 



while there is in 1,000 parts of fresh muscle of the — 



Part 



magnesium. 



Frog 0. 2353 



Shad c 1670 



Eel 1782 



Average 1935 



A comparison of the averages shows for the — 



Magne- Magne- 



Calcium. sium. Calcium. sium. 



Muscles of mammalia 1 : 3. 23 or 0. 31 : 1 



Muscles of frogs and fish 1 : .75 or 1.33 : 1 



Since it is seen that glands contain more calcium than muscles, and 

 that the muscles of lower animals contain more calcium than those of 



«Arch. f. Entwicklungsinechanik, Vol. V, p. 667. 



&If the gray and white matter of the brain are separately analyzed, however, it is 

 found that the gray matter is richer in calcium than the white, as Toyonaga has 

 shown. This is again in accordance with the increase of nuclear mass in the former. 

 It holds good also after the fatty matter is eliminated in both cases. In 1,000 parts 

 of the gray matter of calf's brain was found 0.367 part of lime, while in the white 

 matter but 0.057 part. 



c The unusually large proportion, 0.3102 part, found by Katz in the pike, may 

 possibly be due to an error. 



