The Philippine Journal of Science, 



D. General Biolog)', Ethnologj' and Anthropology. 



Vol. VI, No. 1, February, 1911. 



NOTES ON THE DIGESTIVE SYSTEM OF HYDROCORAX. 



By HOLTON C. CUEL. 



(Surgeon, United States Navy.) 



Because of their peculiar appearance and strange habits, the hornbills 

 have alwaj'S been of popular and scientific interest, and a very large 

 number of articles have been written about them. 



Their method of nesting, mode of flight, and gross anatomy have been 

 abundantly described, while some fairly good accounts of their habits 

 have been given. ^ 



In order to try to learn something regarding the periodical casting-off 

 of the lining of the stomach, as described first by Bartlett,^ I have recently 

 made a series of histological sections of the various parts of the gastro- 

 intestinal tract of Ilydrocorax hydrocorax (Linnseus), and find facts of 

 sufficient interest to record. 



The best results are obtained by taking small portions of tissue from 

 a recently collected bird and jilacing them in a 10 per cent aquous 

 formalin solution for eighteen hours ; from this, the tissue is transfeiTed 

 to 70 per cent alcohol, where it is kept until ready to use. 



Within a few days one may embed the tissues in parafine, cut 

 moderately thin sections, and stain by the Van Gieson or by the hsema- 

 tosylin and eosin method. The Van Gieson stain has the very desirable 

 quality of giving a perfect differentiation. Muscle stains yellow, con- 

 nective tissue stains red, and colloid tissue stains orange. 



By this stain, the muscular coat can readily be separated from the 

 mucous and serous coats, while by its nuclear staining the cells are well- 

 defined and add to the clearness of the picture. 



Before giving a description of the sections, I wish to call attention to 

 several statements, found in standard books, regarding hornbills and 

 which I do not find to correspond with my examinations and observations 

 of Hydrocorax hydrocorax. For example, Newton ^ says that the "horn- 



i Newton, Dictionary of Birds, London (1893), 432-437. 

 - Proc. Zool. Soc. London (1869), 142-146. 

 ' Loc. cit. 



