and Laboratory Methods. 



1471 



reaction of the stomach may be either acid or alkaline, both during digestion 

 and when empty. The reaction is influenced by the nature of the food. For 

 example, when the animals are fed crabs the reaction of the stomach contents is 

 alkaline, while with fish as food the reaction is almost invariably acid. In the 

 species of ScylUmn and Torpedo studied the reaction was found to be always acid. 

 That the reaction of the stomach contents is not due to the specific reaction of 

 the food itself, but that instead there are both acid and alkaline gastric secre- 

 tions, is proven by the fact that the alkaline secretion may be induced by the 

 action of ergot subcutaneously injected. This drug causes certain sphincter 

 muscles in the walls of the blood vessels of the stomach to contract strongly, 

 and at the same time the secretion becomes alkaline. After a time recovery 

 occurs and the secretion becomes again acid. In the case of Scylliicm and 

 Torpedo there are no sphincter muscles in the walls of the vessels, and injection 

 of ergot gave only negative results ; the reaction remained acid. Microscopical 

 examination of the walls of the stomach of Raja clavata, in which the reaction 

 was alkaline, showed the sphincters of the vessels so strongly contracted that 

 there was only a very minute opening in the center. The hindrance of the 

 blood flow caused by this contraction of the walls of the vessels seems to be 

 the immediate cause of the pouring out of the alkaline secretion. r. p. 



Oker=Bloni, M. Eine Normal Elektrode fiir 

 physiologische Zwecke. Arch. f. d. ges. 

 Physiol. 79: 534-536,1900. 



The necessity for frequent change and 

 renewal of its contents is a defect 

 which has long been felt in the ordi- 

 nary physiological, " unpolarisable," zinc-sulphate electrode. These electrodes 



dry up quickly, and if it becomes necessary to use them in contact with different 



fluids, they must be cleaned and refilled 



after each change of condition. Oker-Blom 



has devised an electrode which in large 



measure gets rid of these difficulties, and 



is constant in its working. 



A glass tube, A (Fig. 1), of about 1.2 



cms. diameter and (3 cms. in length, is 



closed at one end and has fastened to the 



side near the closed end a smaller tube, B, 



of the form shown in the figure. Over the 



top of this smaller tube is fitted a small 



cap, bearing at its outer end a camel's 



hair brush. The upper end of the main 



tube is closed by a rubber tube and a 



spring clamp. Into the bottom of the tube 



A is melted a platinum wire, through which 



external electrical connection is made. 



This platinum wire is covered with about 



1 c. c. of quicksilver, over which is placed 



some calomel. The apparatus is then filled with " physiological salt solution " 



(.7 per cent. NaCl). This can be done most easily by removing the cap bear- 



Fig. 1. 



