CH, IX] OF DOMESTIC ANIMALS 319 



semi-solid medium such as faeces, moist earth, etc.; the 

 larvae hatch in from one to four days according to the 

 temperature. They are about 0*21 mm. long and 0'04mm. 

 thick, and are provided with three teeth. Growth is rapid 

 and on the third day after hatching the skin is moulted. 

 In about a week they attain a length of 0*56 mm. They 

 then moult again and throw off their teeth, but may 

 remain within the cast-off skin, which becomes calcareous. 

 In this condition^they can withstand prolonged desiccation, 

 and get blown about by the wind. They are now capable 

 of living free in water, especially if this be dirty. They 

 probably gain access to man in drinking-water, or food 

 contaminated by soiled hands. The adult stage is reached 

 in some weeks after further moults. The worms inflict 

 wounds upon the lining of the intestine, and may cause 

 death. Their presence is indicated by anaemia of the 

 patient and by the presence of the eggs in the faeces. At 

 the present time the condition of the Dolcoath Mine has 

 been greatly improved by forced ventilation, lowering 

 the temperature, by free application of disinfectants to 

 spots likely to harbour infection, and by the enforcement 

 of sanitary rules. 



A closely allied form, Uncinaria trigonocephala, occurs 

 in the intestine of dogs and cats. The male is from 9 to 

 12 mm., the female from 9 to 21 mm. in length. Its life- 

 history resembles that of the last species. After its second 

 moult it can remain alive, though motionless, for many 

 months in water. Domestic animals probably swallow it 

 in this stage with their drinking-water. Another larger 

 form often found in the same hosts is Ascaris nuptaoc. 



