PRODUCED BY ATROPIA IN COLD-BLOODED ANIMALS. 459 



It has also happened that in one or two experiments symptoms of exaggerated 

 activity of the reflex function occurred, without being observed to assume the 

 violence of tetanus. The following is an example of such an experiment : — 



Experiment X. — I injected under the skin, at the left flank of a male frog, 

 weighing 231 grains, one-fifth of a grain of sulphate of atropia, dissolved in four 

 minims of distilled water. In ten minutes, the frog was resting flaccidly on the 

 abdomen and chest. In two hours, all voluntary and respiratory movements had 

 ceased, but stimulation still excited feeble reflex contractions ; and the heart was 

 contracting at the rate of twenty beats in the minute. 



On the second day — twenty hours after the administration— the frog had 

 resumed a natural position, the thorax and head being supported by the anterior 

 extremities, while the posterior extremities were normally flexed ; and the throat 

 and chest respirations were frequent. When the skin was touched, or when any 

 object was rapidly approached to the eyes, a sudden, spasmodic, and momentary 

 contraction occurred simultaneously in the four extremities ; but it was impossible 

 to excite a tetanic convulsion even by severe stimulation. These spasmodic starts 

 — for they were only such— were often preceded by a " croak," and when suddenly 

 and unexpectedly excited, were sufficiently strong to raise the body upwards 

 for about a second. During the following day, these symptoms continued ; but on 

 the fourth day the only symptom was a slight degree of stiffness when the frog 

 jumped. 



On the fifth day the frog was perfectly well. 



It is almost superfluous to allude to the resemblance in frogs between the 

 tetanic symptoms of atropia and those of strychnia. There are, however, certain 

 peculiarities connected with the tetanus caused by atropia — altogether apart from 

 the remarkable circumstance of this tetanus being preceded by more or less com- 

 plete paralysis — that distinguish it from the tetanus caused by strychnia. After 

 poisoning by atropia, the symptoms of exaggerated excitability of the reflex func- 

 tion, as has been shown, are extremely slight on their first appearance, and they 

 acquire their greatest violence only after some considerable time. When these con- 

 vulsant effects have become fully developed, the state of the animal is one of nearly 

 constant tonic spasm — this tonic spasm being rarely general, but almost always 

 restricted to certain regions, — so that the attacks of tetanus are of the nature rather 

 of exacerbations of existing spasm than of successive and independent convulsions. 

 Strychnia tetanus, on the other hand, becomes fully developed with great rapidity; 

 and, during the stage of remission, the animal is usually in a perfectly flaccid state.* 



* Although this is " usually" the case, continuous tonic spasm of the anterior extremities may 

 be produced by strychnia also, if an extremely small dose be given. I have found that a dose 

 equivalent to about the ^ s^Vo^th of the weight of a male frog (or of a female in whom the abdomen 

 is not greatly enlarged by distended oviducts) will almost invariably cause continuous spasm and 

 arch-like flexion of the anterior extremities ; and Tardieu (cjp. cif. p. 983) describes the same effect 

 in an experiment with a minute dose of strychnia. 



