128 Prof. Miiller and Dr. Marshall Hall 



attained through the sympathetic nerve. Yet how can sneez- 

 ing be explained by a connexion of nerves, by v^^hich every- 

 thing and yet indeed nothing can be explained ? We may 

 explain anything by it, because the sympathetic is connected 

 with almost all nerves; and yet nothing can be explained 

 by it, because there is not the most remote reason why a 

 stimulus of this nerve of the nose should produce sneezing 

 and not many other motions, as, for instance, an increased 

 motion of the intestinal canal. Nothing can be explained by 

 it, because in no connexion of the sympathetic with another 

 nerve is there an actual union of their filaments. In sneezing, 

 for instance, there is a violent contraction of all the muscles of 

 respiration ; all the primitive filaments of the intercostal nerves 

 therefore, which produce contraction of the thoracic and ab- 

 dominal muscles, must therein be irritated. But how could all 

 these filaments be irritated from the sympathetic nerve, which 

 adds to each of these nerves a fasciculus of filaments, that, far 

 from uniting its primitive filaments with all the primitive fila- 

 ments of a spinal nerve, only receives them with the latter from 

 the spinal marrow? Now since primitive filaments cannot im- 

 part anything to others lying near them, especially in a motor 

 root without a ganglion, so in this case the sympathetic affec- 

 tion of all the primitive filaments of an intercostal nerve by the 

 sympathetic nerve is a perfect impossibility. All these sympa- 

 thies of sneezing, coughing, vomiting, are done away with, as 

 soon as we know of the reflex function of the spinal marrow 

 and brain, which we have before proved ; and no further diffi- 

 culty lies in the way of the explanation, as soon as one pro- 

 ceeds from the fact, that all respiratory nerves, the facial, vagus, 

 accessorius, phrenic, and the other spinal respiratory nerves of 

 the trunk, by their origin from the medulla oblongata, or their 

 dependence on it, may be easily excited to convulsive motions 

 in muscles, by all stimuli, which are conducted from the sen- 

 sitive nerves of the mucous membranes to the spinal marrow 

 or the medulla oblongata. 



" On every violent stimulus in the intestines, the urinary 

 bladder, and the uterus, contraction of the diaphragm and the 

 abdominal muscles easily ensues, lessening the cavity of the 

 abdomen ; and its contents are forced upwards when con- 

 tained in the stomach (vomiting), or downwards through the 

 rectum or urinary apparatus, or through the genitals as in 

 parturition. The forcible expulsion of faeces is the same 

 phaenomenon in the lower part of the intestinal canal as vomit- 

 ing is in the upper. The forcible expulsion of urine presents 

 the same motions in mental passions; parturition calls into 

 action the same muscles as produce expulsion upwards in vo- 



