Referee report by J. B. S. Haldane on 'On the Chemical basis of Morphogenesis' by A. M. Turing

                                It may well be that I have missed the main points of the author’s 
biochemical argument, but if so, I think other readers would do so.
To a biologist it would seem that the most important deductions 
from the theory arise when the ring of tissue (p.24) becomes very 
large, but the wave length is determined by chemical data (p.28). 
Presumably  this is an approximation to what might happen in a long 
string of tissue, which would then form segments, of equal length ex-
cept near the ends. The author might refer to this point.
The treatment would be easier to follow were the assumptions made 
clear. It appears to be assumed throughout, for example (1) that 
morphogens cannot diffuse out of the organism, which they certainly 
do, e.g. in fungal cultures, and (2) that diffusion through a cell 
wall is very much slower than through the interior of a cell. Such 
assumptions should, I think, be stated.
Again, the genetical theory of p.3 is rather insecure. In many 
embryos (e.g. embryo Salmonidae <u>fide<\u> Svardson) the chromosomes are 
much larger than in adult tissue, and in others (<u>fide<\u> Pasteels and 
Lison) the amount of desoxyribo-nucleic acid per cell is much greater.
There is at least a <u>prima facie<\u> case that there may be a large number 
of examples of each type of gene in a given nucleus. As embryonic 
development is under consideration, this is important.
Again, on p.62 ‘This is gastrulation’ seems an overstatement. 
Localized overgrowth might easily yield a pearshaped form, and the 
kinematics of gastrulation are, in fact, very complicated (cf. Vogt, 
Dalcq, etc.)
The following is a probably incomplete list of errata:
p.6. l.26 ‘1’ omitted.
p.9. l.17 ‘equilib<u>t<\u>ium’
p.13.l. 2 ‘mo<u>t<\u>phogen’; l.8. ‘concentra<u>n<\u>tion’
p.15.l. 8 ‘u<u>sal<\u>ly’
p.16.l.11 ‘le<u>as<\u>t’; l.29. ‘mirro<u>w<\u>’
p.38.l. 9 ?R(t) and t omitted.
p.47.l.25 ‘i<u>a<\u>’
p.50.l.4 ?’C’ omitted 
? on p.30 l.1 = [half] and (8.3) to read