GHOLIN. 293 



The mercurochlorid may exist in two forms : CgHj^NCl + SHgCl^ 

 and CjHjjNCl + HgClj. The former yields colorless, dull, very frag- 

 ile plate-like crystals which are diflScultly soluble and melt at 230°— 

 234°. The latter forms aggregates of very narrow, rather long frag- 

 ile prisms, which are more soluble in water than the preceding and 

 melt at 198.5° - 199.5° (Gulewitsch). 



Physiological Action. — Neurin is exceedingly poisonous, even in 

 small doses, and in its action it strongly partakes of the character- 

 istic stamp of poisoning by muscarin. The injection of a few milli- 

 grams into frogs produces in a short time a complete paralysis of 

 the extremities, with deadening of reflex excitability. Respiration 

 stops first, while the rate of heart-beat gradually decreases till, 

 finally, stoppage in diastole takes place. The injection of atropin 

 at this point does away with the effect of neurin, so that the heart 

 begins to beat again. Previously atropinized frogs, as a rule, with- 

 stand the action of the poison. Immediately after the introduction 

 of this substance there can be observed a distinct period of exalta- 

 tion, which, however, soon gives way to the characteristic stage of 

 depression seen in the progressive slowing of the rate of heart-beat. 

 Of the warm-blooded animals, cats seem to be much more sensitive 

 to its action than mice, rabbits or guinea-pigs. The symptoms seen 

 in rabbits are profuse moistening of the nasal cavities and upper 

 lip, which is succeeded by an intensely profuse salivation ; later 

 on there is noticeable an abundant secretion from the nasal mucous 

 membrane and from the eyes ; the latter, however, ceases in a short 

 time. The movements of the heart and of respiration are at first 

 quickened and strengthened, but before long the paralytic effects 

 produce a constant slowing and weakening till finally complete ces- 

 sation of both movements results. The decided dyspnoea observed 

 gradually alters its character, and just before death the respiration 

 is irregular and superficial. The heart, as in frogs, continues to 

 beat after the respiratory movements have ceased and finally it 

 stops in diastole. Direct application of concentrated solutions of 

 the poison to the eyes produces almost always a contraction of the 

 pupil, while a similar but less constant contraction is seen when 

 it is injected. The peristaltic action of the intestines is height- 

 ened to such an extent that continual evacuation takes place. Just 

 before death, violent clonic convulsions occur. Atropin pos- 

 sesses a strong antagonistic action toward neurin and the injection 

 of even a small quantity is sufficient to dispel the symptoms just 

 described. 



Cholin, C^Hj^NO, = C2HpH.]Sr(CH3)3.0H.— This base is iden- 

 tical with the sinkalin of von Babo, the bilineurin of Liebreich, and 

 the neurin of Baeyer, Marino-Zuco, and others. According to 

 Schmiedeberg and Harnack, it is identical with Letellier's amanitin 



