280 REPORT OF THE COMMISSIONER OF AGRICULTURE. 



worms thus ejected, which they, no doubt, regard as earth-worms, or 

 the red larvae of the large tipulae which resemble them, and of which 

 they are very fond. Two or three weeks later these young pheasants 

 are sure to present symptoms of the malady — the slight, aborted hiss- 

 ing cough, which is so characteristic, and the gaping, which has gained 

 for this disease its English name. 



6. For the purpose of verifying experimentally the accuracy of the 

 facts related above, the authenticity of which, however, did not give 

 rise to any doubt, we fed to a female parrot, on the 7th of August, four 



pairs of large syngames. We had just received from Mine, de la E 



de Montmirail some young pheasants, dead from the gapes, from which 

 we obtained an ample number of syngames ; the parrot being the only 

 subject we had for experiment at the time. On August 2S this bird 

 began to cough and to gape. On September 10 it died, suffocated by 

 numerous syngames which we found, at the autopsy, crowded in the 

 trachea. 



Considering the large number of eggs — several thousand — which a 

 cadaver of the female syngame contains, and the relatively small num- 

 ber of parasites — about thirty or more pairs — which reach their destina- 

 tion, or, in other words, come to maturity, we may form an estimate of 

 the prodigious number of larvae which die on their way or never suc- 

 ceed in finding it. It is, moreover, a law of nature, especially true of 

 parasites, that the number of eggs laid is larger in proportion as the 

 chances of destruction during the earlier period of existence are more 

 numerous. 



The great variation in the size, and hence in the age and the degree 

 of development, noted among the syngames attached to the trachea of 

 a bird shows that there are ordinarily 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 (20°-2o° C.) — prove that the ingestion of water and liquid or 

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

 means of infection perhaps 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 larvae 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 parasite 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. 



