CONTAGIOUS DISEASES OF DOMESTICATED ANIMALS. 117 



a bird showis that there are ordiuarily several successive infections or 

 ingestions of eggs at intervals more or less extensive. This fact may 

 also be due to the circumstance that the conditions favorable to the de- 

 velopment of the parasite have not been the same for all. 



The feeding of healthy pheasants upon syngames filled with eggs, 

 which have been ejected by pheasants suffering from the gapes, is not the 

 only means by which this disease may be propagated. The observa- 

 tions which we have made concerning the vitality retained by the eggs 

 of the parasite when in a moist medium — a medium in which the em- 

 bryos are born and developed if the temperature reaches a suitable 

 height (200-25° C.) — prove that the ingestion of water and liquid or 

 pasty aliments, containing these embryos or eggs, furnishes two other 

 means of infection i)erhaps more active than the first. In every case 

 the only media necessary for the propagation of epidemics of the gapes 

 are food and drink contaminated with the eggs or embryos, and the 

 birds themselves when affected with the disease, as they are then the 

 Source of an abundant emission of eggs of the parasite. No other ani- 

 mated medium, neither adult insect nor larva (the larv£e of ants, for 

 example, which are a constant element of food for young pheasants, and 

 which have been suspected with some appearance of truth), nor any 

 mollusk, in short, can be incriminated. 



MEANS OF DESTROYING THE SYNGAME AND OF ARRESTING EPIDEMICS 



OF THE GAPES. 



The disasters caused by the jiarasite above described in the parks 

 devoted to the rearing of pheasants, point out the extreme importance 

 of finding rapid and effective means of arresting the spread of this de- 

 structive worm. 



A remedy, common in England, consists in mixing the grains which 

 are to be fed to the diseased birds with urine instead of water. Mon- 

 tagu, who tried this remedy without having any faith in its efficacy, was 

 surprised at the success which he achieved, and which proved to him 

 that it was not without utility. It is probable that the ammoniacal 

 emanations arising from the urine are poisonous to the red worm or its 

 embryos. 



^^'i('senthal relates that in America a hen's feather is stripped of its 

 barbs to near the point, introduced into the trachea and rotated like a 

 brush to detach the worms. We strongly question the efficiency of 

 this practice; in the first i)lace, because we know from experience that 

 the worms are too firmly attached to be removed by the friction of the 

 barbs of a feather. Should they be detaclied, however, thej'^ would only 

 be pushed to the root of the trachea, where, forming a ball, they would 

 augment the obstruction in the tube and thus bring about more promptly 

 the death of the bird. On the other hand, the diameter of the trachea 

 of a young i)heasant from five to six weeks old, being scarcely equal to 

 that of the shaft of a hen's feather, will not permit the introduction of 



