204 INTRODUCTION TO THE WORMS 



unclean probosces of biting flies, bugs or other insects. We have 

 not yet fully awakened to the importance of an uninjured mu- 

 cous membrane. As has been pointed out by Shipley^ the in- 

 testinal worms play a part within our bodies similar to that 

 played by blood-sucking arthropods on our skins, except that they 

 are more dangerous since, after all, only a relatively small per 

 cent of biting insects have their probosces soiled by organisms 

 pathogenic to man, whereas the intestinal worms are constantly 

 accompanied by bacteria, such as Bacillus coli, which are capable 

 of becoming pathogenic if they gain access to the deeper tissues 

 as they are able to do through the injuries made by hookworms, 

 whipworms, tapeworms, etc. Weinberg, for instance, found that 

 whereas he was unable to infect unparasitized apes with typhoid 

 bacilli, apes infested with tapeworms or whipworms readily con- 

 ,_ trac-ted -ty-phoid fever, the bacteria presumably gaining entrance 

 through wounds in the mucous membrane made by the worms. 

 The relation of intestinal worms to appendicitis is more than 

 hypothetical, and it is probable that far more cases of appendi- 

 citis are the outcome of injury done by worms than is usually 

 supposed. Although it has been objected that very few of the 

 thousands of appendices removed yearly are reported to contain 

 parasites, it must be pointed out that parasites are very seldom 

 sought, could easily be overlooked, and might not be recognized 

 as such if found. It is furthermore possible that parasites which 

 initiated the inflammation and ulceration might no longer be 

 present in the appendix upon its removal, since they are able to 

 move about freely in the digestive tract. Shipley remarks that 

 appendicitis is a commoner disease now than it was when ver- 

 mifuges were more frequently given. 



Diagnosis. — The diagnosis of infection with various species 

 of worms often depends on the identification of their eggs or 

 larvae as found in the fseces or other excretions by microscopic 

 examination. Nearly every species of parasite has recognizably 

 distinct characteristics of the eggs, the chief variations being in 

 size, shape, color, thickness of shell, amount of development, 

 appearance of the embryo if present and presence or absence 

 of a lid. Some of the commoner worm eggs are shown in a 

 comparative way in Fig. 61. 



