Paper, 'Action of caffein and theine upon voluntary muscle' by T [Thomas] Lauder Brunton and J [John] Theodore Cash Brunton and Cash write: 'From a number of experiments we have found that caffein [caffeine] and theine both cause rigor in the voluntary muscles of frogs. All these experiments were made on Rana temporaria and none on Rana esculenta.' Annotations in pencil and ink. Subject: Physiology Received 24 March 1887. Read 31 March 1887. A version of this paper was published in volume 42 of the Proceedings of the Royal Society as 'Action of caffein and theine upon voluntary muscle'. 1887