Kyder.] --UU [April 7, 



liave its wall folded into ridges, with intervening fissures that tend, for 

 assignable mechanical laws, to join one anollier at an angle of 120°, as 

 first pointed out by the late Dr. A. J. Parker, and, as it seems to me, cor- 

 rectly attributed by him in part to ergogenetic influences. It may also be 

 sliown tliat the heart, in the course of its development, gives evidence of 

 being subject to the morphogenetic influence of ergogenJ^ 



The spiral or torsional form of many of the articuhir faces of the ends 

 of bones in the limbs of terrestrial vertebrates can probably be shown to 

 be associated with the development of torsional stress in locomotion. 

 That such torsional stress is actually developed during the locomotion of 

 terrestrial vertebrates has been conclusively proved by Prof. Allen from 

 a careful study of the work of Muybridge upon animal locomotion. Upon 

 every hand, therefore, there is evidence of structure that has been devel- 

 oped in conformity with the conditions of the expenditure of animal 

 energy. I have myself called attention to the fact that digital reduction 

 first began in the hind limbs or in those subjected to the greatest stress, in 

 leaping, b}' land vertebrates. The forelimbs show this tendency later and 

 in conformity with the fact that they cannot become the channel for the 

 dissipation of such large amounts of energy, impulsively, as the hind 

 ones. Digital reduction and specialization is therefore to be regarded as 

 having been induced and begun ergogenetically. 



In the course of other work I have had occasion to call attention to the 

 fact that the foundations of the skeleton were in every case laid down in 

 certain comparatively inactive, or, as I have elsewhere expressed it, ameta- 

 bolic tracts. These tracts were either external, protective non-plasmic 

 envelopes or they were developed between the organs. In both cases 

 they tend to take the form of intercellular or circumcellular matrices, or 

 as matrices laid down between organs. Metabolism is nil in them every- 

 where because of the non-plasmic and the non-metabolic character of 

 their substance. Such matrices, therefore, present from the lowest pro- 

 tozoa up to the highest metozoa tolerance of inert foreign matters within 

 their substance. !Such matrices being colloid, they often attract inert cal- 

 careous or silicious matters that are held in solution in the circulating 

 fluids as deposits, just as such deposits are seized and held under labora- 

 tory and non-vital conditions by colloids in the presence of hypersaturated 

 solutions. In other words, there is here a tendency to revert to a statical 

 condition on the part of these inert salts, which thus lend to crystallize 

 within such a matrix and within the living body. These matrices are 

 thrown out as a protection, or as the result of irritation of cell tracts, or 

 to increase the volume of an organism ; the colloids of which they are 

 composed attract the inert calcareous or silicious salts that pass through 

 the living and adjacent plasma and a statical equilibrium is thus restored. 

 The skeletal maiilx thus calcifies, as we express it, whereas the trutli is 

 that «/e are probably dealing with a phenomenon that differs but little in 

 its essential nature Irom one that may be imitated in the laboratoiy. The 

 process is one that ultimately develops a st.ttical equilibrium when the 



