Why is the axon of neuron called white matter and why is cyton grey in color? If it's because of the white colour(in the former case), where does the white colour come from? Fat deposits(myelin sheath)? But the whole axon is not so? then?

Why is the axon of neuron called white matter and why is cyton grey in

1.	Why is the axon of neuron called white matter and why is cyton grey in color? If it's because of the white colour(in the former case), where does the white colour come from? Fat deposits(myelin sheath)? But the whole axon is not so? then?
Answer» Why is the axon of neuron called white matter and why is cyton grey in color? If it's because of the white colour(in the former case), where does the white colour come from? Fat deposits(myelin sheath)? But the whole axon is not so? then?