550 S. AVALTER RANSON 



divided into several lobes connected by narrow necks; (3) com- 

 plicated pericellular networks formed of great nmnbers of fine 

 branches and collaterals; and (4) glomeruli of fine fibers occupying 

 the capsules of dead cells, and formed by collaterals from adja- 

 cent axons. 



Similar observations on transplanted ganglia have been made 

 by Marinesco and Minea ('07-'08), and by Agosti ('11). Quite 

 similar changes have been seen when spinal ganglia have been 

 cultivated in vitro (Lengendre and Minot '11, and Marinesco 

 and Minea '12, '14). 



Our own observations confinn those of previous investigators 

 that simple unipolar cells may be transformed under experimental 

 conditions into complex multipolar cells. An additional fact of 

 unportance brought out by this investigation is that such multi- 

 polar cells can return again to their original simple form. 



In this work white rats were used, two for each experiment. 

 The anunals receiving the graft varied in age from one month 

 up. The grafts were taken from animals of varying ages, some 

 only one week old. The head of the recipient was prepared and 

 a small strip of bone removed parallel to the superior sagittal 

 sinus, and an incision made in the cerebral cortex in line with the 

 bone defect. A warm pack was then placed over the wound and 

 the second cervical spinal ganglion removed from the neck of 

 the second rat. The ganglion w^as grasped with fine forceps by 

 a short stretch of attached nerve and inserted into the brain 

 wound in such a way that the nerve was deepest in the wound 

 and the ganglion just beneath the cortex. 



The first experiments were made in 1905. At that time three 

 successful transplantations were made. In each of these experi- 

 ments the recipient was one month old, and the donor a week old. 

 Two animals were allowed to live ten days and one two months. 

 The brains from the first two animals were examined for the site 

 of the graft and this with a piece of the surrounding cortex was 

 excised. Paraffin sections from these were stained with toluidin 

 blue and erythrosin. The third brain was prepared by the Pal- 

 Weigert method and counterstained with Upson's cannine. 



