466 HANDBOOK OF PHYSIOLOGY. 



muscular coat of that and the adjacent part of the canal. But if irritant 

 substances be mingled with the food, the sharper stimulus produces a 

 stronger impression, and this is conducted through the nearest ganglia to 

 others more and more distant; and, from all these, reflex motor impulses 

 issuing, excite a wide-extended and more forcible action of the intestines. 

 Or even through the sympathetic ganglia, the impression may be further 

 conducted to the spinal cord, whence may issue motor impulses to the 

 abdominal and other muscles, producing cramp. And yet further, the 

 same morbid impression may be conducted through the spinal cord to 

 the brain, where it may be felt. In the opposite direction, mental influ- 

 ence may be conducted from the brain through a succession of nervous 

 centres the spinal cord and ganglia, and one or more ganglia of the 

 sympathetic to produce the influence of the mind on the digestive 

 and other organs; altering both the quantity and quality of their secre- 

 tions, 



2. Transference. 



It has been previously stated that impressions conveyed by any cen- 

 tripetal nerve-fibre travel uninterruptedly throughout its whole length, 

 and are not communicated to adjacent fibres. 



When such an impression, however, reaches a nerve-centre, it may 

 seem to be communicated to another fibre or fibres; as pain or some other 

 kind of sensation may be felt in a part different altogether from that 

 from which, so to speak, the stimulus started. Thus, in disease of the 

 hip, there may be pain in the knee. This apparent change of place of a 

 sensation to a part to which it would not seem properly to belong is 

 termed transference. 



The transference of impressions may be illustrated by the fact just 

 referred to the pain in the knee, which is a common symptom of disease 

 of the hip. In this case the impression made by the disease on the 

 nerves of the hip-joint is conveyed to the spinal cord; there it is trans- 

 ferred to the central ends or connections of the nerve-fibres which are 

 distributed about the knee. Through these the transferred impression 

 is conducted to the brain, which, referring the sensation to the part from 

 which it usually through these fibres receives impressions, feels as if the 

 disease and the source of pain were in the knee. At the same time 

 that it is transferred, the primary impression may be also conducted to 

 the brain; and in this case the pain is felt in both the hip and the knee. 

 And so, in whatever part of the respiratory organs an irritation may be 

 seated, the impression it produces, being conducted to the medulla ob- 

 longata, is transferred to the central connections of the nerves of the 

 larynx; and thence, being conducted as in the last case to the "brain, 

 the latter perceives the peculiar sensation of tickling in the glottis, 

 which excites the act of coughing. Or, again, when the sun's light 



