PROCEEDINGS 



OF THE 



BIOLOGICAL DEPARTMENT 



OF THE 



ACADEMY OF NATURAL SCIENCES 



OF PHILADELPHIA. 



1859. 



Reported by Dr. Walter F. Atlee, Recorder pro tem. 



Dr. Joseph Leidy, Director. 

 January and February. 



I. Anatomy. 



1. Dr. Hammond exhibited the stomach of a musk rat (Fiber zibethicus,) in order 

 to show the peculiar glandular apparatus of the organ in this animal. 



Dr. Hammond stated that having occasion recently to dissect one of these 

 animals, he had observed a fact calculated to prove of interest to this Depart- 

 ment. 



On opening the stomach, a round spongy mass about an inch in diameter was 

 found to occupy the pyloric extremity of this viscus. Upon subjecting it to 

 microscopical examination, it was ascertained to be composed of a mass of 

 tubules similar to those found in other parts of the stomach in the vertebrata 

 generally. The whole secretory apparatus was concentrated in this mass, the 

 remaining portion of the stomach being entirely devoid of any such arrange- 

 ment, consisting simply of a rugous mucous membrane, the muscular layer, 

 and the serous coat. 



A somewhat similar construction exists in the beaver, (Castor fiber,) and is 

 described by Cuvier in his Anatomie Comparte. 



Dr. Hammond had also ascertained that in the genus Arvicola (embracing the 

 common water rat,) the same formation and arrangement of the gastric tubules 

 exists. 



Dr. Hammond was not aware that attention had hitherto been directed to 

 the structure of this peculiar formation in the animals in question, and hoped to 

 be enabled to extend his researches on the subject. 



II. Physiology. 



1. Dr. Mitchell exhibited a microscopical specimen of prismatic blood crystals 

 obtained from the dried blood of the opossum, (D. Virginiana.) Dr. Mitchell 

 also exhibited blood crystals obtained from the putrescent blood of the mnsk- 

 rat, Fiber zibethicus. These crystals were rhomboidal tablets measuring a half 

 to two-thirds of a millimetre in length. They formed spontaneously in a phial 

 of blood which had stood in a warm room for five weeks, and was very putrid 

 and of a most unbearable odor. 



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