I'll definitely go get the body of his comments and post them to this thread.
I believe you are incorrect on this point, however. Only when the cell has divided into two distinct bodies are there two souls present.
Duo sunt in homine refers ONLY to each man's having a soul ... as reflected in his having two sources of knowledge: ratio (which he shares with lesser creatures) as well as intellectus, that fragment ofi spiritual light by which he has recourse to an intuitive knowledge of truth.