EXAMINATION OF SOME SPINAL NERVES 137 
the central nervous system), progress, and are in a sense cumulative. Tlie decreasing depression 
merges — at present inextricably for us — in the increasing onset of an ' isolation-alteration.'* 
Much of what is called ' shock,' in regard to the Mammalian cord, is, I believe, due to ' isolation- 
alteration,' and is really permanent, that is to say, would not pass away if the animal were to live 
healthily for any number of years. The most favourable time for the examination of the 
independent capabilities of the spinal cord is that when the sum of ' shock ' and ' isolation- 
alteration ' together is of smallest amount. That time, compounded as it is of two such variable 
factors, is itself extraordinarily variable. In result of spinal transection in Monkey, I am sure that 
' shock ' lasts longer, and that ' isolation-alteration ' comes on earlier than in the other animal types 
commonly observed in the laboratory. It is the conjunction of the periods of these two 
phenomena which renders so difficult and so largely defeats attempts at observations on proper 
spinal reactions of the Monkey. If the overlap of the two is great, then no spinal reflexes, or only 
the merest traces of them, may be observable. In Man it is only natural to suppose — and what 
clinical experience I have had access to strengthens me in the belief — that even more than in 
Monkey will ' shock ' be protracted, and ' isolation-alteration ' speedy and severe. The 
observations of BASTiAN,t Bowlby,! and Bruns§ teach us that the clinical picture of the effects 
of total transverse lesions of the human spinal cord does not accord in the way that medical text- 
books have been wont to describe with the long-known results obtained from the transected cord 
by the physiologist. Older physiological experiments are, however, not based on nervous systems 
so approximate to the human as is that of Macacus^ Cercocebus, Sic. Of these latter I would say 
that their condition after spinal transection commonly resembles in its features, in the most striking 
manner, the condition of spinal depression observable after transverse spinal lesion in Man, and 
considered by Bastian to be the typical status. 
My results on Monkeys bear out strikingly and fully what Bastian describes as the typical 
condition in Man after complete transverse destruction across the cord. The chief diflPerence 
is that in the Monkey in most cases — partly, perhaps, because the lesion is more localized by 
experimental infliction than by accidental — the depression is not so severe. For instance, the 
knee-jerk, which disappears almost immediately after the transection, returns usually in a week or 
ten daysjil often, however, not for three weeks ; occasionally, on the other hand, in ten minutes. 
Rules observable in Spinal Reflex Actions. 
I will now attempt to state and illustrate such rules of reflex action as seem capable of 
induction from the above observations. In the first series of the following pages I shall refer only 
to reflexes of short path, to short spinal reflexes. 
In doing this, use must be made of the terms ' spinal segment,' ' short spinal reflexes,' 
' long spinal reflexes,' and ' spinal regions.' The spinal segment is often loosely, though arbitrarily, 
* Munk's ' Isolations-anderung,' a term which expresses what I mean, has been introduced by him to denote aheration 
lesulting from a lesion of cortex cerebri. I venture to introduce the word in the above wider sense. 
+ ' Medico-Chirurgical Transactions,' 1891. London. || Sherrington, ' Journ. of Physiol.,' vol. 13, 1892 ; 
X Ibid. A. S. F. Grilnbaum, 'Journ. of Physiol.,' 
§ ' Neurologisches Centralblatt.' Berlin, 1893. vol. 16, 1894, p. 368. 
S 
