1884.] NATUEAL SCIENCES OP PHILADELPHIA. 115 



careous shells of Foraminifera, the beautifully sculptured frustules 

 of Diatomacese,keen siliceous needles, and the sharp armatures of 

 minute Crustacea. 



In the fore-part of the intestinal canal, the food mass, staining 

 almost as readily as the wall of the gut itself, seems to merge into 

 the ill-defined epithelium of the latter, and it is scarcel}'^ possible 

 to say where the food-bearing mucous thread ceases and the 

 intestinal epithelium begins, especially as this latter has a rugous 

 arrangement. That we have here to do with a form of digestion 

 entirel}^ anomalous and unprecedented, he could not believe, and 

 must beg leave to differ from Dr. Korotneff on this point. Foland 

 others have recognized the endostyle as a sort of salivary gland, 

 and have traced its food-laden mucous thread into the stomach of 

 the living animal, while the speaker had been able to trace the 

 same thing in well-preserved specimens. He had also several 

 series of sections from animals which must have been without 

 food for some time previous to death, in which the lumen of tlie 

 intestine is not only free of food, but of any obliterating mass of 

 cells, or Plasmodium. The only protoplasmic bodies not food, 

 are certain Gregarina-like organisms adhering to the walls of 

 various parts of the intestine, and which he took to be parasites. 

 These give on section the appearance of the large "scattered cells, 

 entirely free from their surroundings " which Korotneff figures 

 and regards as " analogous to the great stomach-cell of Anchinia.''^ 

 The first opportunity would be taken to examine these structures 

 in living Salpse, but he was now forced to conclude that Dr. 

 Korotneff has endowed the food-bearing mucous thread with a 

 power it does not possess, that Salpa does not exhibit any 

 unusual form of intracellular digestion, and that there is no im- 

 mediate cause on its account for questioning the high genetic 

 place occupied by the Tunicates. 



A Preliminary Note on a Reaction common to Peptone and Bile- 

 salts. — Dr. N. A. Randolph stated that if the acid nitrate of 

 mercury (Millon's reagent) be added to a cold aqueous solution 

 of potassium iodide, a red precipitate of mercuric iodide always 

 appeal's. When, however, either peptones or the biliary salts are 

 present in noteworthy amount, the precipitate of nascent mercuric 

 iodide assumes the yellow phase. As practicallj^ applied, the 

 red may vary from salmon to scarlet, the yellow from pale 

 lemon to orange. 



In order to render the test sensitive to the presence of minute 

 quantities of the substances in question, he had found it necessary 

 to limit the amount of potassium iodide employed. Thus to each 

 five cubic centimetres of the suspected fluid — which must be cold 

 and either neutral or faintly acid — are added two drops of a 

 saturated solution of potassium iodide, the two liquids being well 

 mixed. Four ox fiv« drops of Millon's reagent are now added, the 

 contents of the vessel thoroughly stirred or shaken. Under these 



