ECOLOGICAL SUCCESSION. 147 



The proof of ecological succession must re-t on the result - 

 experimental \\ork on the animal- of the different stages of -uch 

 a horizontal series. // matters not from the point of : 

 ecological succession ichat the forms > lon^ as the arc 



':rev.t in the different > horizontal ml the 



i'li a '//.'< ;; :'ed icith the environmental conditions. 



When -urli difference- and relation- are found, ecological -IK . 



-cniially -lied. h is ol .i/ed that 



within raiher uncertain limit.- the > ..f a morphological 



-p< rn.iin. in a :< ner,'.! way. the same throughout it- geo- 



Thi- kind of rea-oning mu-t In- pursued \\i;h 



i. union. Whi-n applied in detail or to "common" species \\hieh 



\\ ide '-.m-iii^, it i- i ill trustworthy, [f, for example, an 



aiination of ihe de;i>-it- in i!n- bottom of a pond, sue!; 

 I'ond l j. showed the pr fish \\hirh now habitually 



inh.tliit- the you >\ pond -i ion, let it U- a more 



ii'Mihern, or tin hose in i he hori/oiita! series 



und r cor \\oiild con-tiiiitf -oine e\ ideii( 



logical -i!' -i \\hieh could lie Itirther checked \-\ the -tud\- 



o| the modili.'.l'ili". of the mores of that -,prcje- at pre-ent. 

 HOV in tin- kind . ! t \ ideiice lie crucial. 



I iirthei mori . the i-iiidition- -tich a- \\rre in prim.ie\al I'ond 

 l | i ould ha\e been i'e. ichrd I -\ a pond like I'ond I in .1 feu hun- 

 dred- of \. In a pi nd \\itl: I mori MlilaMe ill. ill -and 

 for the -rouili :llt-, the-e cliail, id lake p ! 

 \\ithin the life time ..f the lualder of Mich a pond Knauthe. '07. 



I'- 5; 



\ I. i .i NIK \l I >!- i SSION. 

 We noted in the precedin. r that physiographic analysis is 



a nieih<id. Heieu. \ . d a i lot her met hod \\ hich , \\ h i le 



not ph\ -io-r.iphic, i- ,-imilar in principle, -ince it deal- \\iih 

 -ucce i"ii over .' ^i\en locality. The cause of thi- succession 

 i- liiolo-ical and the biological ii, :- proportioiiateK greater. 



We ha\e here the -aille attempt to disCOVer -omelhiilL' of the 

 ph \-iolosJca I character of the or-ani-m as a whole, and to classif} 



ini-ni- on the ba-i- of the conlitioii- in which the\- are nm-t 

 iitarK in ph\ -i"l".^ical e<]iiilibritun. A;j;ain, the mures ol the 

 li-h of pond Stages in other parts of 'he \\orld are probably Minilar 

 if the pond- are -iniilar. 



