16 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 



over the end of the rod. They now find themselves on the 

 skin, and in all probability they burrow their own way in 

 through the skin and so are not injected with the blood as 

 was naturally at first thought. Here then we have an example 

 of a nematode worm for the transmission of which an inter- 

 mediate insect host is necessary. What becomes of them 

 and what happens to them from the time they enter the skin 

 to the time at which they are found as adults in the lymphatics, 

 is unknown. 



Ankylostomiasis. 



This is a disease due to the presence of minute worms 

 about one-third of an inch long that live in the gut of man. 

 They bury their heads in the gut and produce their serious effect, 

 in all probability, by a poison that they secrete into the wound 

 that they make as they feed on the submucous layer of the 

 gut. The ravages caused by this parasite in the Southern 

 States of America are widespread, and the Americans are now 

 making a great attempt to stamp out the disease. The mode 

 of attack is two-fold. 



(1) Medicinal. Luckily the worms are amenable to 

 treatment, and in the drug Thymol, first used by Bozzolo 

 in 1880, we have a potent weapon. (2) Improved sanitation. 

 In order to understand how this is applied we must first 

 understand the life-history of the worm. The worms live 

 in the gut of man. Their eggs pass out in the excreta. Here 

 they hatch and become larvae. These larvae are able to 

 penetrate the skin, so that a person walking bare-footed on 

 contaminated soil is very likely to get infected. The larvae 

 as they pass through the skin cause a good deal of itching. 

 They eventually, by a circuitous route through the lungs 

 and trachea, get swallowed and so pass down the gullet into 



