450 DR T. R. FRASER ON SOME UNDESCRIBED TETANIC SYMPTOMS 



the structures on whose affection they depend; and (D), to harmonise these 

 effects with analogous ones in warm-blooded animals, and explain their 

 appearance in certain special circumstances only, in both frogs and mammals. 

 This investigation is limited to the consideration of these objects. Only those 

 effects of atropia that are directly connected with the convulsive symptoms will, 

 therefore, be considered. 



SECTION A. 



Soon after a small fatal dose, or one rather less than fatal, of a salt 

 of atropia is administered to a frog, a slight degree of weakness occurs in the 

 anterior extremities ; the respiratory movements of the chest cease, those of the 

 throat continuing; and the motor power becomes gradually more and more 

 impaired, until at length no voluntary or respiratory movements occur, and the 

 animal lies on the abdomen and chest in a perfectly flaccid state. If the condi- 

 tion of the heart be now examined, it will be observed that the cardiac impulse 

 is scarcely perceptible, and that the contractions are reduced to a very few in the 

 minute. At this time, the application of various stimuli shows that the func- 

 tions of the afferent and efferent nerves and of the spinal cord are retained, 

 though in a greatly impaired condition. 



Several hours afterwards — it may be not until the following day — the action 

 of the poison is still further advanced ; for the afferent and efferent nerves are 

 completely paralysed, while but an occasional and scarcely perceptible cardiac 

 impulse can be discovered, the only signs of vitality being this imperfect cardiac 

 action, and the retained irritability of the striped muscles. This condition may 

 last for many hours, or for several daj^s. Previous observers have apparently 

 mistaken it for one of death, and have therefore failed to observe the symptoms 

 that subsequently appear, and to which, more particularly, I wish to draw 

 attention. 



The first of these symptoms is usually caused by a change that occurs in the 

 flaccid condition of the animal; the anterior extremities becoming gradually 

 more and more flexed, until they assume a state of rigid and continuous 

 contraction, with the webs pressed either against each other, or against the 

 opposite elbows — tonic spasm of the muscles of the chest helping to keep the 

 anterior extremities in this position. At this time, a touch of any portion of the 

 skin increases the spasm of the anterior extremities and of the chest muscles, 

 and causes some slight spasmodic movements in the posterior extremities. After 

 a varying interval, the respiratory movements reappear, the cardiac action 

 improves greatly in strength and in frequency, and the posterior extremities 

 assume an extended position, with the webs more or less stretched. If the skin 

 be now touched, a violent attack of tetanus occurs (at this time usually opistho- 

 tonic), which may last for from two to ten seconds, and which is succeeded by a 



