34 The Ohio Journal of Science [Vol. XVII, No. 2, 



stage, i. e., for 12 stages, the increase by mitosis during this 

 period would be 120 nuclei. This leaves a margin of 80 nuclei 

 for error and possible increase in rate of growth during the 

 stages. 



This count of the nuclei seems to fully confirm the other 

 evidence for the fusion intact of the ganglia in question and 

 leave no doubt of its certainty. 



The question, however, of the possible disintegration of 

 the Profundus portion in later stages where its identity is in 

 part lost deserves attention. The evidence for disintegration 

 is slight for the boundaries of profundus becomes more and more 

 definite from early stages up to the time of fusion and there 

 is slight evidence of shelling off of cells into the mesenchyme. 



If the profundus disintegrated one would expect to find 

 an increasing looseness in the mass and increasing difficulty 

 in determining its boundaries up to the time of fusion. So far 

 as I have observed the opposite is true, during its development. 

 The profundus never behaves as a disintegrating structure, 

 but in fact always contains some mitotic figures which are 

 proofs of continued growth. The comparative rate of growth 

 of the Gasserian and profundus through all stages in their 

 development has not been determined, but the comparative 

 rate at the selected stages furnishes significant proof that 

 the profundus is not breaking down. 



In the 6 mm. stage there is one figure in profundus and 

 there are two in Gasserian. The rate of growth is slow for both 

 ganglia at this stage, which is soon after their formation, and 

 for several series the chief characterisitc of their behavior is 

 the aggregation of cells. In the 7 mm. stage there are 10 

 figures in the two ganglia combined and seven of these are in 

 the profundus. This is a period of comparatively rapid growth 

 and the rate of growth is much higher in the profundus than in 

 the Gasserian. The profundus is evidently the more active 

 of the two ganglia. In the 9 mm. stage there are only four 

 figures in the ganglionic complex. This is the beginning of a 

 period of differentiation and of the formation of fibrous roots 

 and nerve trunks and is marked by a slowing up in the growth 

 process. Even at this stage, however, the profundus is as 

 active as the Gasserian. 



Aside from the facts just cited there are other evidences 

 of the persistence in the trigeminal complex of the profundus. 



