9Q 



THE GUIDE TO NATURE. 



for a perfect body are present. Such 

 has been the idea of Darwin and other 

 natural philosophers of the first rank. 



THE CRAB'S CLAW 



Weismann has constructed the most 

 elaborate of present day theories as to 

 the nature of these germinal particles 

 and the method of their distribution to 

 the proper parts of the developing 

 body. "When the organism is com- 

 pleted the determinants are, accord- 

 ing to this hypothesis, thoroughly dis- 

 tributed, and each small region of the 

 system has in it only the determinants 

 proper to that region. Yet as some 

 parts of the body are liable to be 

 broken off— such as the appendages of 

 the lobster or the brittle tail of the sal- 

 amander — nature has here and there 

 provided reserve funds of deter- 

 minants. The first formed leg or tail 

 being accidentally lost, these reserve 

 determinants come into play and cause 

 the tissues which sprout out to take 

 the right form. 



Such theorizing doubtless seems 

 very speculative. Yet just these bold 

 guesses at the invisible factors of the 

 process have led the way to most fruit- 

 ful researches. This is the reason for 

 thinking that it pays to discuss them. 



Let us see how Homoeosis as ex- 

 hibited by our crab's claw affects the 

 idea of Weismann that the determi- 

 nants, allowing that such bodies really 

 exist, are thoroughly sorted out and 

 distributed to their appropriate bodily 

 members in development, and so be- 

 come the means of making the parts 

 take their proper shapes. 



If the determinants or governors of 

 form are sorted out into each bodily 

 member according to its kind, then a 

 given piece of a crab's claw should 

 have only the determinants for that 

 particular piece, as, for example, the 

 back of the dactyl. Or. at most, it 

 may have a certain supply over and 



above the demands of first growth, to 

 guide a second if that is required by 

 the loss of the original piece of claw. 

 And if that piece is lost, by the theory 

 only that piece can grow again in that 

 place, the determinants of all other 

 bodily parts being absent from this 

 one. 



But when our crab gets into a quar- 

 rel with a neighbor and the neighbor 

 bites out a portion of his claw, and 

 when the wound edges, irritated by 

 the removal, proceed to build up the 

 breach, behold, the growing tissues 

 take not the form suitable for filling in 

 the gap, but of almost an entire claw, 

 teeth and all ! In these growing tis- 

 sues, therefore, there must be, if we 

 grant that there are any such govern- 

 ing bodies at all, the determinants for 

 a nearly complete claw. 



These particles must be in the wound 

 edges; for from these all the growth 

 starts. And we must suppose that 

 they were there before the wound was 

 made. Suppose the wound to have been 

 a very little deeper or less deep or a 

 little to the right or left of the place 

 where it actually occurred. Would 

 the new growth still have been a nearlv 

 perfect claw? In all nrobability it 

 would have been so. Then we must 

 suppose that cells throughout this par- 

 ticular region contain determinants, if 

 any, for a whole or nearly a whole 

 claw. 



This conclusion, the reader will see, 

 is much against the idea of the strict 

 distribution and sorting out of form 

 giving particles in the development of 

 the body. 



Perhaps there are no such special 

 form governors residing within the 

 cells of the tissues. But if not, how 

 then is the growth and development 

 of the body managed with such pre- 

 cision that not once in hundreds of 

 thousands does any part fail to arise 

 in its proper place or to take on the 

 shape, color, etc., which it should have? 



We cannot think of any such thing 

 as ideas, apart from substance and 

 structure, transmitted from generation 

 to generation. If we say, "Law," then 

 the law must have something material 

 to execute it. We know nothing of 

 biological law anart from material 



