ON WHAT IS "A COLD"? 131 



instance, and after retiring to bed in the latter, he is 

 "taken with a desire to sneeze," and, yielding to the 

 impulse, does so, with the effect or result that his nose 

 "begins to run," and he finds himself the subject of a 

 "cold in the head." 



How is this? It is thuswise the exposed cutaneous 

 surface suffers a chill, the peripheral sensory nerve fibres, 

 in association with the sympathetic ganglionic corporeal 

 advance-guard, determine and cause the contraction of the 

 muscular structures of the skin, producing, it may be, 

 cutis anserina y when the local and cutaneous or peripheral 

 nerve structures, with their surrounding sheaths and con- 

 tained cerebro-spinal or nervine fluid, become in turn 

 compressed, with the result that their fluid contents, their 

 outward or cutaneous points of exit being thus closed, are 

 pushed forwards or, if you like, backwards until more or 

 less escapes into the cerebro-spinal cavity like railway 

 "rolling stock pushed into a 'lie,'" which suddenly 

 increasing the volume of the contents of these already 

 sufficiently full intra-spinal and intra-cranial spaces and 

 inter-spaces, the situation thus created is relieved by an 

 overflow into the nasal cavities, preceded by the required 

 act of sneezing or "open sesame" determined by the dis- 

 charge of the necessary reflex motor impulses to the 

 necessary muscular organisms. 



A " cold" a " simple cold " in this case thus becomes 

 the type of that class of diseases which have for their 

 origin and cause the operation of a purely mechanico- 

 nervous influence, and, therefore, into the consideration 

 of which chemico-zymotic problems do not enter. 



From thus following one by one the various occurrences 

 in the ' * sequence of events " characterising and making 

 up this pathological entity, and obtaining a clear insight 

 into the causation and progress of the ailment, we are 

 warranted, after searching for "indications for treatment" 

 and "prescribing" on simple and purely scientific lines, 

 in saying that, if our opinion were sought in this or such 

 a case, " trust the operations of the vis medicatrix nature ." 



In pursuing our enquiries a little further in this twilight 

 or dawning region of medical science, where the 'scene of 

 the growth of modern descriptive medicine and pathology 



