THE CRAB-LOUSE 83 



Nuttall(l) makes out of the mode of spread of 

 the pest be correct, it could play little part in the 

 development of epidemics. By analogy, young 

 hatching from the eggs should be unable to cause 

 typhus or trench fever, though if the parent were 

 infected with relapsing fever the offspring might 

 be able to convey that complaint (see p. 106). 



It is recorded that when numerous these lice 

 may cause a simple fever which disappears when 

 the parasites are removed. It is therefore pre- 

 sumably caused by the action of the salivary 

 juice injected and not by any organism. The 

 bites often cause no itching at all, so that a person 

 may be heavily infested and know nothing of it. 

 In other cases the itching may be very severe, 

 the variation being according to the individual 

 peculiarities of the infested. A curious effect of 

 the bite is that frequently blue patches appear 

 on the skin at the spots where the insect has been 

 feeding (2). 



REFERENCES 



(1) NUTTALL, G. H. F. " The Biology of Phthirus pubis," Parasito- 



logy, vol. x. pp. 383-405. 



(2) NUTTALL, G. H. F. " The Pathological Effects of Phthirus pubis" 



Parasitoloyy, vol. x. pp. 375-382. 



