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history and embryonic forms of many of these creatures. The 

 subject is of great importance, for large numbers of both human 

 beings and animals perish each year through their agency. 

 Moreover, it is not far removed from that great question which 

 occupies so prominent a position before the medical profession at 

 the present time. I refer to the germ theory of disease. The 

 one is an animal, the other a vegetable parasite. The method of 

 artificial culture is now being used for working out the latter; I 

 see no reason why it cannot be successful in the former. 



EMBRYOLOGY AND DEVELOPMENT OF SYNGAMUS. 



The egg is formed out of the granular material seen near the 

 extremity of the ovarian tubes. It is shaped into small round 

 bodies which pass down towards the uterus, within the horns of 

 which they are supposed to become impregnated, and receive 

 the hard external coat called the shell. The egg in syngamus 

 becomes perfect under favorable circumstances about fourteen 

 days after earthworms containing the embryos are fed to a chick. 

 It is then oval, about .004 inch in its long, and .0025 inch in its 

 short diameter. At each end is a valve or lid which drops off 

 when the embryo emerges from the egg. 



We believe the egg of syngamus, within the perfect worm just 

 arrived at maturity, does not contain a developed embryo. We 

 are aware it is generally thought by naturalists that the eggs 

 furthest advanced in a mature syngamus contain the perfect 

 embryo, already moving actively about within the shell. We will 

 briefly give the reasons for our opinion. In experiment No. 8, 

 it will be seen that a chick, fed earthworms containing the 

 embryos of syngamus, developed the gapes, and in fourteen 

 days from the time of the first feeding great numbers of the 

 eggs of syngamus were found after they had passed through the 

 fowls' intestines. These eggs passed from perfect worms, which 

 were found breaking up in the trachea of the chick killed the 

 same day. Now the eggs which passed through the chick, and 

 those found about the perfect worms in the trachea, showed no 

 sign of embryonic formation. Moreover, we will say that after 



