84 HAND-BOOK OF PHYSIOLOGY. 



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 ganglia of the 

 spinal nerves, and through them 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 loefeU. In the opposite direc- 

 tion, mental influence may be conducted from the brain through a suc- 

 cession 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 secretions. 



2. Transference. It has been previously stated that impressions 

 conveyed by any centripetal nerve-fibre travel uninterruptedly through- 

 out 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 apart 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 sen- 

 sation 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 sign 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 transferred 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 oblongata, 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 per- 

 ceives the peculiar sensation of tickling in the glottis, which excites the 

 act of coughing. Or, again, when the sun's light falls strongly on the 

 eye, a tickling may be felt in the nose, exciting sneezing. 



A variety of transference, which may be termed radiation of impres- 

 sions, is shown when an impression received by a nervous centre is dif- 

 fused to many other parts in the same centre, and produces sensations ex- 



