CHAPTER VII 

 THE HOOKWORMS OF MAN AND ANIMALS 



TECHNICAL SUGGESTIONS 



Ancylostoma caninum affords the most satisfactory laboratory type 

 for the study of the hookworms. In almost any section of this 

 country a systematic examination of several freshly killed laboratory 

 dogs and cats, or dogs and cats from the city pound will furnish 

 abundant material. If necessary, specimens mounted or unmounted 

 can be purchased from dealers. 



The worms should be thoroughly shaken in a vial of clean water 

 to remove mucus and debris from the mouth region, and then killed 

 in hot 70 per cent alcohol plus 5 per cent of glycerine. When the 

 alcohol has been allowed to evaporate, they may be mounted in 

 glycerine jelly and sealed with Noyer's cement. Very satisfactory 

 preparations may be made by passing from plain 70 per cent alcohol 

 to lactophenol mixture in which the specimens are mounted. For 

 temporary examination either lactophenol or 80 per cent carbolic acid 

 in absolute alcohol may be used. Such temporary mounts are 

 preferable for small classes with abundant material since they allow 

 manipulating of the specimen. 



Eggs may be obtained in quantity by removing the rectal content 

 of an infected dog or cat, sedimenting by several changes of water 

 in a tall bottle, straining through a close-meshed sieve (e.g., a tea 

 strainer), and preserving in 10 per cent formalin. Random exami- 

 nation of feces of cats and dogs will often yield abundant material. 



For larval stages cultures should be made by mixing fecal material 

 containing eggs with equal parts of animal charcoal or, heat-sterilized 

 humus moistened with water and stirred to a paste. The moisture 

 content being maintained, they are kept for a week in a warm room or 

 in an incubator maintained at 25 to 30°C. and then isolated by means 

 of the Baermann apparatus (see Appendix) or by the simple method of 

 White, 1927. The culture is early placed in a Syracuse watch glass in 

 a crystallizing dish with water equal to about half the depth of the 

 watch glass, and the whole is covered by a large watch glass. The 

 larva? as they reach the infective stage wander from the culture into 

 the water and may be recovered in numbers by pouring this off 

 into a test-tube, in which they will settle to the bottom. 



An instructive demonstration of the nematode population of the 

 soil is afforded by placing a pint of rich garden soil in the Baermann 

 apparatus for a few hours or overnight and draining the sediment 

 into a large test-tube. A culture of infective hookworm larvae should 



39 



