Ten full-time fetus fixed by formalin were used in this experiment.Ten pairs of anterior roots (C_6

C_7

C_8

T_5

T_(11)

L_3

L_4

L_5

S_1 and S_2)were cut off from each fetus

embedded by paraffin sliced in serially longitudinal section being 10μ thick and stained by means of Nissl method.Under the light microscope

we observed and counted the neurons.The results were as follows: (1).1259 neurons in all were observed in the 198 anteriir roots of the ten fetus.One of the roots had 79 neurons being the greatest number.No neuron was observed in 38 anterior roots. (2).The neurons are often arranged singly or by threes and fives.They dipersed in all parts of the anterior root. (3).The neurons are round or oval

the nuclei are round

the nucleoli are large and distinct.Nissl bodies are slightly granular add distribute evenly. Each neuron is surrounded by a ring of capsule cells (satellite cells) which belong to sensory neurons in form. (1).The significance and originate of the appearance of neurons are ana- lysed and discussed in this article.