20 THE ACTIVE FORCES OF LIVING ORGANISMS 



is found in many parts of the body, amongst others 

 in muscular tissue and in red blood corpuscles, and 

 its presence in these regions may seem to contradict 

 that which has just been said. But it must be borne 

 in mind that the formation of any substance, and its 

 appearance in a given locality, may be totally separate 

 events, and it is very probable that those localities 

 in which red blood corpuscles are formed — such, for 

 instance, as the cancellous tissue of bone — are not 

 seats of active but of restricted oxidation. The supply 

 of blood in the red marrow is abundant, it is true, 

 but the flow of blood is slow, and there is very little 

 movement of any other kind. If we suppose lecithin 

 to be formed in such a region, the supply of phos- 

 phates in the bone itself would seem to be a not im- 

 probable source whence the minute quantities of phos- 

 phorus required are drawn. Whatever be the truth 

 in regard to this point, it is evident that, when such 

 substances as lecithin and protagon are formed, which 

 are, comparatively speaking, poor in oxygen, this gas 

 must in some way be kept in the background. 



The composition of the three bodies above men- 

 tioned is such that, if broken up, the amounts of each 

 of the elements carbon and hydrogen would be able 

 to combine separately with, or absorb more — and in 

 the case of the cerebral compounds very much more 

 — than, the quantity of oxygen present. It is a very 

 debatable point whether, in addition, the presence of 

 phosphorus renders these compounds more than 

 usually liable to become oxidized. With respect to 



