ANCYLOSTOMA DUODEXALE 455 



lymphatic path leads finally also into the blood stream, but the 

 lymphatic glands must first be passed, and in these many larvae are 

 retained and perish. In the cutaneous infection seven to ten weeks 

 elapse till the time of appearance of the first ova in the faeces. 



The penetration of the skin by the larvae also in man causes reddening and 

 burning at the affected points, and this is followed in a few days by transitory swell- 

 ing in the subcutaneous connective tissue. Skin affections can also be set up by 

 such Ancylostoma (and Strongyloides) larvae as do not gain access to the blood or 

 lymphatic vessels or gut ; such larvae apparently wander further in the connective 

 tissue, and, as Looss has in his own person observed, gain access to the cutis at 

 different points, thus causing progressive swellings (accompanied by intense itching), 

 which cease when the worm again penetrates into the deep tissues. Skin affections 

 such as " ground-itch " or " pani-ghao " occurring in the tropics and only attacking 

 the feet, or other affections (e.g., sump bunches) are now well recognized as being 

 due to the invasion of Ancylostoma larvae. 



Other names for these skin affections are water-sore, sore feet of coolies, maza- 

 morra, bunches, botches, quaddeln, kratze, ampoules, gourmes, taons, pitirr. 

 Whether oral or dermal infection is the more important one further observation 

 must decide. 



The duration of life of Ancylostoma duodenale, which is a specific 

 parasite of man and has not been observed in other mammals, 

 amounts to about five years, as strayed larvae according to Looss 

 wander for this extent of time in the body. 



Cultivation of Larvce.(i) Mix the faeces (free from drugs such as 

 salines or thymol) with animal charcoal, adding water if necessary 

 till a consistence of porridge is obtained. If the stools are very fluid, 

 allow to sediment first and pour off the fluid. The best charcoal is 

 that made from bones, and should not have an acid reaction. Char- 

 coal is necessary in order to prevent fermentation, which kills the 

 larvae. Spread in layers 2 to 3 mm. thick in Petri dishes. Incubate 

 at room temperature. To extract the larvae from the culture allow 

 the surface thoroughly to dry, then pour on water ; the larvae 

 wander out and are poured off and subsequently further purified by 

 sedimentation or filtering through blotting paper, the larvae passing 

 through. 



(2) A funnel is plugged with cotton wool, then filled with washed 

 sand to within a centimetre or two of the rim. Stand this in a jar of 

 water so that the level of the water is slightly below that of the sand. 

 On the surface of the wet sand now place layers of blotting paper, 

 and spread the faeces, diluted if necessary, on this in layers of a few 

 millimetres thick (vide p. 474). 



Detection of Eggs. Vide p. 473. 



Dermal Infection of Dogs. Infection with larvae of A. caninum. 

 In two hours most of the larvae are free in the cutis and in four hours 

 in the subcutaneous tissue. By scraping a few days later the mucosa 

 of the trachea large numbers of larvae are found there. 



