86 Ingvar Jorgensen and Walter Stiles. 
We give below some remarks of Grignard (1913) on this subject. 
“ Avec cette extraordinaire faculte d’adaptation aux molecules 
chimiques les plus diverses, le magnesium ne serait-il pas capable 
de jouer un role trks actif dans les syntheses naturelles de la 
matiere organisee ? 
Willstatter a, en effet, reconnu que ce metal s’accumulait, pour 
ainsi dire, dans une substance douee d’une activite catalytique 
considerable, la chlorophylle. 
11 a isole des chlorophylles les plus diverses des combinaisons 
contenant jusqu’a 3-5% de magnesie. Et il a conclu de ses etudes 
qu’il doit se former des combinaisons analogues aux organomag- 
nesiens et que l’absorption du gaz carbonique par la chlorophylle 
serait tout k fait analogue k une reaction de Grignard. II est arrive 
ainsi k comparer la chlorophylle des feuilles k l’hemoglobine des 
animaux et a penser qu’il y aurait pour la mati&re vivante deux 
cycles de transformation: la vie de synthese avec l’aide du 
magnesium et la vie d’oxydation avec l’aide du fer. 
II reste cependant k trouver sous quelle forme le magnesium 
peut s’approprier a ces reactions, dans un pared milieu, si different 
de celui oil nous sommes habitues a le voir triompher. Ce sera le 
probleme de demain.” 
A further instalment of Willstatter’s theory appears in his 
book (1913, pp. 23-25), which again we give in the form of a 
translation of Willstatter’s own words. 
“ The role of magnesium can be imagined to be the same as in 
those organo-magnesium compounds discovered by Barbier and 
Grignard which have attained such importance in organic synthesis 
on account of their reactive properties. Already in our first 
communication (1906) on the analysis of chlorophyll a parallel is 
drawn between the latter and the Grignard compounds. The 
parallel appeared to be inaccurate and met with contradiction 
because it took no notice of the difference between the binding of a 
metal to carbon in the ordinary organo-magnesium compounds, and 
the substitution with nitrogen in chlorophyll. But we do not consider 
this difference either distinct or characteristic. 
Since our publication, B. Oddo has carried out important 
investigations on pyrrole magnesium iodide which reacts with 
carbon dioxide and with acid chlorides resulting in the formation of 
& substituted pyrroles, & carbopyrrole acid, and alkylpyrrylketone. 
Probably the N-magnesium derivative is first formed, and this is 
either transformed into the ^-magnesium compound, or reacts as 
such, e.g. 
