BUEEAU OF ANIMAL INDUSTRY. 553 



the two older cliicks, one died September 8, without any worms in tbe 

 trachea ; the other was killed September 16, no worms found. 



Thus our success was only partial, both in feeding earth-worms and 

 embryo of syngames, while Dr. Walker obtaiued very positive results 

 with both modes of infection. 



The foregoing experiments show that earth-worms of infected places 

 ilo contain the embryo. They also show that the earth-worm is not a 

 necessary host, and therefore JMegnin's views as given in the j)receding 

 report remain still in full force. The embryo is without doubt present 

 iu the earth-worm for the same reason that particles of earth, leaves, 

 &c., are present. The earth-worm in boring into the soil must fre- 

 quently swallow the earth that lies in its way, as pointed out by Dar- 

 win. That ova of syngames should be swallowed in this way is quite 

 natural ; and the embryos may even be used as food, and in that case 

 killed before they leave the alimentary canal of the earth-worm. So 

 that the question whether earth-worms are really injurious to farmers 

 in eating ova or embryos of syngames can hardly be decided in the 

 affirmative from these experiments. To Dr. "Walker, however, belongs 

 the credit of having pointed out the iuteresting fact that earth-worms 

 of infected grounds may produce the disease in chicks which feed upon 

 them. 



Dr. Walker examined the alimentary canal of infected earth-worms 

 carefully and found therein i^arasites which he believes were the em- 

 bryos of Syngamus trachealis. We examined a number of worms sent 

 by him very carefully, but failed to demonstrate the presence of any 

 embryo smaller than the nematodes, which were quite uniformly present 

 in the body cavity and inhabit the segmental organs. These measured 

 about .5™°» (.02 inch) in length. Dr. Walker gives the length of the 

 smaller embryo as .0118 inch. A certain gregarina ( G'. agilis ?) was also 

 frequently observed. 



Dr. Walker also tried artificial culture of the embryos which he ob- 

 tained from the alimentary canal of the earth-worm. For this purpose 

 he used blood serum, into which they were placed and then kept in an 

 incubator. The blood serum was changed every day. Some worms 

 died within two days; others lived for five or six days, during which 

 period he observed some to molt. The rapidity with which blood serum 

 decomposes at a high temperature, the toxic effects of the products of 

 putrefaction, and the poverty in respirable oxygen of this medium make 

 such experiments difficult of execution and uncertain in results. 



Dr. Walker suggests that the earth-worms of infected poultry-yards 

 be destroyed. To do this the ground is to be covered with lime, salt, 

 or ashes, of which substances he prefers the salt. 



As to the possibility or desirability of exterminating the earth-worms 

 from poultry -yards where gapes exist among the fowls, the experiments 

 made are neither sufficiently numerous nor so definite in their results as 

 to admit of a satisfactory conclusion. That chicks may contract gapes 

 by feeding upon earth-worms that contain the embryos of Syngamus is 

 demonstrated, but it has also been demonstrated that this is not the only 

 way by which this parasite gains entrance into the body of the chick. 

 To destroy earth-worms Dr. Walker recommends saturating the earth 

 of poultry-yards with a solution containing 1 or 2 pounds of salt to a 

 gallon of water. All interested in this subject should carefully read, in 

 in connection with the present remarks, the details of the measures of pre- 

 vention suggested by M. Megnin (First Annual Report of the Bureau 

 of Animal Industry, pp. 292-295); and iu case of failure to arrest the 

 disease by these measures, an attempt may be made to destroy the 

 earth-worms according to the recommendations of Dr. Wallcer. 



