CHOLINE AND ALLIED SUBSTANCES 59 



taneous oxidation and reduction (Cannizzaro's reaction) amino-ethyl 

 alcohol and amino-acetic acid (glycine) are then supposed to be formed 

 from the aldehyde. 



CH 3 OH + NH, CH 2 . NH 2 



2. CH 2 -> | i | 



CHO CHO 



formaldehyde glycollic aldehyde amino-acetaldehyde 



CH 2 . NH 2 CH 3 . NH 2 CH 2 . NH 2 



CHO CH 2 OH COOH 



+ H 2 

 CHO 



amino-acetaldehyde amino-ethyl alcohol glycine 



In his recent book on the simple plant bases Trier [1912, 3, p. 33] 

 has modified the above hypothesis and imagines that glycollic aldehyde 

 first undergoes Cannizzaro's reaction and that the two products of this 

 reaction (glycol and glycollic acid) then condense with ammonia 



CH 2 OH CH 2 OH CHoOH 



2 I + H 3 +1 



CHO CH 2 OH COOH 



glycollic aldehyde glycol glycollic acid 



CH 2 OH CH,.NH 2 + H O 



| + NH* = I 



CH 2 OH CH,,OH 



glycol amino-ethyl alcohol 



CH 2 OH CH 2 . NH 2 



I + NH 3 = | +. H 2 



COOH COOH 



glycollic acid glycine 



Amino-ethyl alcohol and glycine are the simplest units for the forma- 

 tion of proteins and phosphatides respectively, and hence it becomes 

 intelligible why, as Stoklasa has pointed out, protein and lecithin 

 formation are two parallel processes. An argument for the biological 

 significance of Cannizzaro's reaction is the occurrence of a number of 

 alcohols as esters of the corresponding acid (e.g. benzyl benzoate and 

 cinnamyl cinnamate in balsams ; cetyl-palmitate C 16 H 31 O 2 . C 16 H 33 occurs 

 in spermaceti and ceryl cerotinate C. 27 H 53 O 2 . C 27 H 55 in Chinese wax). 



A ferment causing Cannizzaro's reaction (" aldehyde mutase") has 

 been recently found in liver extracts by Parnas and by Batelli and 

 Stern (see Dakin's " Oxidations and Reductions in the Animal Body," 

 pp. 105, 1 06, in this series of monographs). 



In addition to Thudichum, Trier, and Baumann, who isolated 

 amino-ethyl alcohol, other investigators have suggested that phos- 

 phatides may contain bases similar to choline but containing fewer 

 alkyl groups. These investigations however require careful scrutiny in 

 the light of recent knowledge. Koch [1902] applied Herzig and 

 Meyer's method for the estimation of N-methyl groups to kephalin and 

 cerebrin and concluded that one N-methyl group is present in kephalin 

 none in cerebrin, and three in lecithin. Frankel and Neubauer, like 



