538 Veterinary Medicble. 



ing, concentration of the bile, the presence of colloids and bac- 

 teria infection. 



Idleness is especially operative in cattle, which are quite subject 

 to biliary calculi and concretions, when shut up in the stall on 

 abundant, dry feeding for a long winter. They are not noticed 

 in stalled animals, that are fed watery or succulent rations, such 

 as green fodder, distiller's or brewer's swill, ensilage, brewer's 

 grains, mashes, roots, potatoes, apples, pumpkins, and in case a 

 tendency to their formation is developed on the dry feeding nf 

 winter, the concretions may be re-dissolved and entirely removed 

 by the succulent spring grass. A similar influence is noticed in 

 the human family, as the female sex living mostly indoors, and 

 males pursuing sedentary occupations furnish the greatest number 

 of gall stones. 



Concentration of bile results in part from muscular inactivity 

 and hepatic torpor, but also from over-feeding which loads the 

 portal blood and indirectly the bile with an excess of solids, and 

 from dry feeding which lessening the secretion of water leaves 

 the bile more dense and predisposed to precipitate its solids. The 

 density of the liquid, however, developed from a rich and dry 

 ration and a prolonged inactivity, may continue for a length of 

 time, without the occurrence of actual precipitation. It usually 

 requires some additional factor to make this predisposition a 

 direct cause. 



Presence of Colloids. This may be found in the presence 

 of solid or semi-solid particles. Just as the introduction of a 

 thread into a concentrated solution of sugar or salt will induce 

 an instant crystallization on a filament so the presence of solid 

 bodies determines a similar condensation in solid form of the 

 solids of the bile. But this tendency is increased materially if 

 the solid body is itself of a colloid or non-crystallizable material. 

 Rainey and Ord have shown experimentally that colloid bodies 

 like mucus, albumen, pus, blood, epithelial cells, not only de- 

 termine the precipitation of crystallizable salts from a strong 

 solution, but that they cause the precipitate to assume the form of 

 globular or spherical particles, which by gradual accretions on 

 their surfaces tend to grow into calculi. They found that salts 

 which are deposited by mere chemical reaction, without the in- 

 tervention of colloids, appear in the form of sharply defined 



