No. 607] DTFFEFEXrTATIOX IN TTIE OJWAXISM 



423 



intensely, ri-(M|U('iii i\ (li\-i(lc .-nid ilicii' >l met ure iinderp:oes 

 rai)idly a scries of cliaii.uvs wJiicli arc not always identical 

 and which 1 raiisfoi'iii theni into vai-ion^ hlodd cells. Do 

 these various changes exchisively depend npeii the 

 physicocheniical constitution of the cells, in other words 

 are tliey |)i-(Mh.'stiii(Hl. will each of tlicsc cells urow into 

 a definite unit, nialt<'r to wlial condition it is subjected? 

 Is tlie gi-ou)* of aniehold, moi-) iliologically similar cells 

 freed from the niesenchynial syncytiuni still formed by a 

 numl)ei- of species cells, the charactei'istics of which con- 

 sist if not in a discernible structure, >(■[ in an inheiont 

 necessity to develop along definite lines .' 



A sei'ies of investigations, some of them my own. have 

 ])ointed to tlie group of the free aniel)(»id ceils as the 

 mother colls of various blood elemenis. In regions where 

 the isolation is merely 0(N'a>ional. -.-ntlered wandering 

 cells arise. In regions wliere tii<' isolation of free cells is 

 intense, so-called anlages of lieniaioii«»iei ic oi'-aii> de- 

 velo]>. The first stages of dexclopmenl ot' \arloiis lienia- 

 to]>oietic organs were found to lie much alike and tlx- con- 

 tinuous differentiation of the \-ai'ious hlood cells through- 

 out life was shown to have for its startim:- point a eell, 

 the structure of which is similar to that of the ami'lioid 

 cell, wdrich arise from the m.-encliyme. 



Moreover. i1 u a^ ol.^erve.l that there exited an invaiiahle 

 assnrinfinu l.rt>rrr„ (hr ,! r r rl„ pu, r Hi of fhr mnfhrr rrll ilifo 

 a <hiiuiir IdnofI rrll OH^l ^1 r fi H i I r r ur i ro u >U r >it 'll r,nu1ifio,IS, 



viz., if left in tlu^^pace^amon-M me^ench^ malcelU the free 

 ameboid cell develop^ into a -ranulohlaM. e^Mvially in 

 the vicinity of thin walled ve<>el<: if -^un'ounded by endo- 

 thelial wails and Hibjected to Int rnvaM-ular c..ndItion> it 



