22 THE PHYSICAL BASIS OF LIFE 



other, or by a iiiodifieatioii of this process may split up 

 into secondary more limited systems according to a deti- 

 nite and predetermined plan. To this subject, so impor- 

 tant for our conceptions of embryological development, 

 we shall presently return ; but this can better be appreci- 

 ated after a broader survey of the origin of the cyto- 

 plasmic formed bodies in general, a prol^lem which now 

 opens before us with a new significance. 



Laying aside all merely speculative attempts to solve 

 this problem, we must admit that our actual knowledge 

 concerning it is still in a very backward state. An impor- 

 tant group of observers, led by Benda and Meves,* have 

 urged the possibility that many of the formed bodies may 

 arise by the transformation of chondriosomes, possil)ly 

 also of Golgi-bodies, that are themselves transmitted by 

 cell-division ; but too nmch emphasis should not be laid on 

 this view, which has met with nmch opposition and still 

 remains of doubtful, or at best restricted, validity. It 

 is still a widely prevalent l^elief that many of the formed 

 bodies arise de novo, i.e., that they are built up anew in 

 the cytoplasm by localized processes of chemical and mor- 

 j^hological synthesis; but in respect to this (piestion we 

 may readily fall into error. Permit me to illustrate this 

 by reference to some old ol^servations of mine on those 

 classical objects for the study of protoplasm, the trans- 

 parent eggs of certain sea-urchins and star-fishes.^^ 



When mature these eggs show with great l^eauty a 

 structure that has often compared to an enmlsion, con- 

 sisting of innumerable spheroidal bodies suspended in a 

 clear continuous basis or hyaloplasm. These bodies are of 

 two general orders of magnitude, namely, larger spheres 

 or macvosomes, rather closely crowded and fairly uniform 

 in size, and much smaller microsomes irregularly scat- 

 tered between the macrosomes ; and among the latter are 



