1470 Journal of Applied Microscopy 



tubules nor with any other epithelial structure can be traced : (b) that the 

 morphology of such cells, as shown by Volkmann, Krompecher, and others, is of 

 very slight importance in their identification with epithelial or endothelial 

 structures ; (c) that direct transitions between the obviously connective tissue 

 elements of the stroma and these cells occur ; (d) that intercellular fibrils can be 

 demonstrated between the cells of such masses by the use of Van Gieson's stain ; 

 and (e) that the spaces in which such cell masses occasionally lie have not, like 

 the alveoli in carcinomata, any further lining endothelium — concludes that it is 

 justifiable to consider these cells of endothelial rather than of epithelial nature. 

 Hence he classes the tumor as an endothelioma, rather than a carcinoma. 



J. H. p. 



GENERAL PHYSIOLOGY. 



Raymond Pearl. 



Books and papers for review should be sent to Raymond Pearl, Zoological 

 Laboratory, University of Michigan, Ann Arbor, Mich. 



Weinland, E. Zur Magenverdauung der Hai- This paper treats in considerable detail 

 fische. Zeitschr. f. Biol. 41 : 35-68, Taf. I, ^f ^^le digestive processes and functions 

 "^ ■ of the anterior part of the alimentary 



tract in the selachians. As living material individuals of the following species 

 were used : ScyUiiim catidus and canicula ; Torpedo ocellata and fnarmorata : 

 and J?aja asterias^ clavata and glauca. The chemical reactions of the stomach 

 contents were also studied in dead specimens of a number of other species. 

 The method used for obtaining the secretion of the gastric glands in a pure con- 

 dition from the living animal is ingenious and seems to have given excellent 

 results. Briefly, the procedure was as follows : one end of a glass siphon of 

 from 10 to 15 mm. diameter was thrust down through the mouth well into the 

 cavity of the stomach, and allowed to remain there until a sufficient amount of 

 the fluid contents of the stomach had passed out. Meanwhile artificial respiration 

 was maintained by passing a current of water over the gills. The oesophagus 

 closed tightly over the siphon so that there was no risk of any mixture of sea 

 water with the stomach contents. The treatment apparently has no ill effect on 

 the animal, as the author states that he has in some cases daily emptied the 

 stomach of the same animal by this method for considerable periods of time 

 (fourteen days and over), without causing any injury. This method should be 

 widely applicable, both for purposes of investigation and class demonstration. 



The principal points discussed are : (1) the length of time the food remains 

 in the stomach, and (2) the chemical reaction of the stomach contents. It was 

 found that the food remains in the stomach for a considerable time ; from two to 

 three days in the majority of cases, up to eighteen days in one instance observed. 

 The food is generally completely disintegrated in the stomach, forming a fluid or 

 semi-fluid mass. The animals studied were able to live for several months at a 

 time without taking food. 



It appears clearly from the experiments that in the living skate (^Raja') the 



