488 ELECTRO-PHYSIOLOGY CHAP. 



of the mucosa after, as well as before, continues to produce a 

 strong negative variation in the existing rest current. After large 

 doses and longer poisoning we frequently found not merely that 

 the incoming current of rest was considerably weakened, but that 

 the results of direct electrical excitation were reduced in a marked 

 degree. The conclusion is that atropin principally paralyses the 

 gland nerves, without seriously injuring the cells. 



It may be taken as proved that not only the glands of the 

 external skin, but nearly all the glandular organs, are essentially 

 affected by pilocarpin, as regards their state of activity, in the 

 sense of a long-protracted, energetic excitation. Having ourselves 

 (80) thoroughly investigated the action of pilocarpin poisoning upon 

 the morphological behaviour of the lingual glands in the frog, it 

 was the more interesting to determine the concomitant galvanic 

 phenomena. In experiments many times repeated, in which 

 the (non-curarised) frogs were injected with 1 cc. of 2 / Q 

 solution of pilocarp. muriat. under the skin of the back, we 

 invariably found two hours afterwards that the entering mucosa 

 current of the tongue (which was covered with a visible layer of 

 secretion) was developed with unusual vigour, and was often of 

 considerable proportions. Corresponding with this, the negative 

 variation, both with direct and indirect excitation, was extremely 

 pronounced, and nothing has come under our notice so well 

 calculated to exhibit the above-described normal reaction of the 

 tongue in excessive proportion, as pilocarpin poisoning. 



With regard to the action of this drug it was to be expected 

 a priori that a long -protracted excitation of the secretory 

 nerves would produce a similar effect. As in the salivary 

 glands, so too in the mucous glands of the frog's tongue, it is 

 possible by introducing a metronome into the circuit of the 

 secondary coil to extend the excitation of the corresponding 

 secretory nerves over several hours, without fear of too rapid ex- 

 haustion of the glands. Deep-seated histological changes ensue 

 in both cases, which are in close relation with the secretory 

 process (80). 



If, during such rhythmical persistent excitation, the electro- 

 motive phenomena are observed in the tongue (which should 

 preferably be in situ, with intact circulation), there will be found 

 without exception after a longer or shorter period during which, 

 the initial current appears weakened in consequence of the pre- 



