LARKSPUR POISONING OF LIVE STOCK. 17 



from the readily available evidence, and recourse must be had to 

 a study of the contents of the rumen. On account of the maceration 

 of the plants most of the material is unrecognizable on macroscopic 

 examination, the leaves especially being almost disintegrated. Fre- 

 quently, however, stems of grasses and other plants retain their 

 structure sufficiently to show some characteristic features, the fibro- 

 vascular bundles in many cases being more or less intact when the 

 looser tissues have been disintegrated. 



As the poisoning due to DelpMniuTn harbeyi was being investi- 

 gated, an attempt was made to determine whether the stomachs of 

 the poisoned animals contained this plant, by comparing sections 

 of stems found in the rumen with sections of stems of Delphinium 

 harbeyi. In this way it was found possible to determine whether 

 an animal had eaten larkspur, and this method was successfully 

 applied in a number of cases where portions of stomach contents 

 had been preserved in formalin. This work led to the sectioning 

 of stems of other species of Delphinium in order to discover whether 

 it was possible to differentiate between the species by stem sections, 

 especially since in the .region where the station was located two 

 species of larkspur occur. This work is here recorded, not in any 

 sense as a complete study of the stem anatomy of the genus, but 

 as a few interesting facts brought out by a comparison of cross 

 sections of stems of a number of species of Delphinium. 



In looking up the literature of this genus, no anatomical work was 

 found on "the American species. A number of articles have been 

 published both in Europe and America on the anatomy of the Ranun- 

 culacese as a whole and of some of the other genera, but those deal- 

 ing with Delphinium in detail are few and are European. In 1885 

 Albert Meyer published an article on the systematic anatomy of the 

 Ranunculacese, in which he grouped the genera according to anatomi- 

 cal characters, and also differentiated many of the species, giving a 

 key based on anatomical characters. His work was on the char- 

 acters shown by cross-sections of stems. Paul Marie, 1885, pub- 

 lished an extensive paper on the histological structure of the Eanun- 

 culacese. In this work the detailed anatomy of all parts of the plant 

 is described for a number of species in each genus, and the dis- 

 tinguishing characters of the family and of the different genera 

 are discussed. The only article which is devoted solely to the anat- 

 omy of Delphinium is that of Lenfant, 1897, on the genus Delphin- 

 ium in a series of contributions to the anatomy of the Ranunculacese. 

 The histological structure of four species (two of which, ajacis and 

 consolida., have been introduced into the United States) is studied 

 for all parts of the plant and for various stages of growth. 

 26876°— Bull. 365—16 2 



