114 FLORENCE R. SABIN 



The series of sections from which the model was made, extended 

 only just through the region of the mid-brain. It was the hope 

 at that time, to procure a series of sections of the entire brain of 

 the new-born babe so as to complete the modeling of the tracts into 

 the thalamus and cerebrum. The especial goal was to throw some 

 light on the form relation of the internal capsule. Since that time 

 five series have been cut in this laboratory, three of the new- 

 born brain, and two of the brain stem and basal ganglia of the 

 adult. Of these series, three are in the sagittal plane, while one 

 of the baby's brain and one of the adult were cut in transverse 

 series. The sagittal series of one of the adult specimens was cut 

 by Miss Gertrude Stein. It has proved most valuable. Miss 

 Stein made a model of the medullated tracts in one of the series 

 of the new-born brain, but it proved that the gaps in the series 

 were sufficient to prevent an interpretation of the model . From the 

 series on which the present study is based, two models have been 

 made, the first one was by Dr. E. G. Gowans, of Salt Lake City, 

 who modeled the thalamus and basal ganglia on one side. Un- 

 fortunatel}^ Dr. Gowans' work was unavoidabl}^ interrupted and 

 as there was little chance that he would be able to take it up again, 

 I have completed it. In studying Dr. Gowans' model I found 

 it hard to interpret the bundles in the thalamus without includ- 

 ing those of the brain stem, and hence made a new model of 

 the brain stem and thalamus of the other side of the same brain. 

 The figures are all taken from my model, but the study covers all 

 the work done in this laboratory on this topic by Miss Stein, 

 Dr. Gowans and myself. I am indebted to Miss Stein for series 

 she prepared, and to Dr. Gowans both for the model and for 

 his study of the subject by which I benefit. The specimen from 

 which the model was made was brittle and while in thick 

 cellodin the brain stem cracked from the thalamus. The cellodin, 

 however, was thick enough to hold the two parts in exact apposi- 

 tion, as can be seen in figs. 5 and 7. The plane of the section is 

 oblique as can be seen in the same two figures, since the raphe 

 is included in the sagittal section (see no. 61, fig. 5). This 

 only increases the difficulty in the pihng of the model but does 

 not affect its accuracy. I believe that the model does throw some 



