276 Journal of Comparative Neurology. 



prising how many writers are satisfied with these superficial 

 findings of tracts, without attempting to look for corresponding 

 cell-bodies to complete the neurones. The time when ascend- 

 ing and descending degenerations and the length of the tracts of 

 degeneration would pass as a description fit for publication is by- 

 no means over and much splendid material is thus half-way 

 wasted because it is not exhausted with better methods of pre- 

 paration and study. 



One would think that the frequent cases of compres- 

 sion of the spinal cord surviving from a week to several months 

 would have been used for settling what the degeneration meth- 

 od can settle in the anatomy of the spinal segments. In the 

 vast majority of the few studies published, neither the cells nor 

 the cephalic ' tracts ' have been decently studied. Lately the 

 writer received two such specimens, without spinal ganglia and 

 without oblongata and brain. My well-meaning friends evidently 

 have no exact conception of the extent of neurones. 



Well-established 'systems' might well be called foundlings; 

 we know nothing of the mother-cells from which they come. 

 Among these are: Gowers' tract, a system of neurones consti- 

 tuting afferent elements from the lumbar cord-segments to the 

 cerebellum and the midbrain ; the so-called anterolateral de- 

 scending tracts, which may come from the cerebellum, or mid- 

 brain or from Deiter's nucleus; the septo-marginal and comma- 

 tracts which most probably do not come wholly from the affer- 

 ent neurones of the spinal ganglia. It would further be impor- 

 tant to revise the work of Flechsig from the neurone point of 

 view ; espcially his idea of * systems ' which, he says, are the 

 same as will degenerate in locomotor ataxia. I am inclined to 

 attribute much of the common superficiality to the way stu- 

 dents are usually taught. The phrases commonly used are : 

 such a tract degenerates upward or downward and therefore 

 conducts upward or downward. This may be shorter, and more 

 easily remembered than the following attitude of mind dictated 

 by the neurone-theory : any destruction of nerve fibers leads to 

 a rapid decay of tJic pai't of tJic fiber cut off from its mieleus, while 

 the fiber stump remaining in connection with the cell will usually 



