74 
Lice and Disease 
VI. NOTE ON THE PRESENCE OF ANTICOAGULINS IN THE 
SALIVARY GLANDS OF P. HUMANUS. 
That anticoagulins are present in the salivary glands of lice was 
demonstrated by the following experiments conducted with clothes-lice 
received in May, 1916, from Dr Hamer in London. The method 
pursued was that described by Nuttall and Strickland in connection 
with similar experiments made on Argas persicus (see Parasitology, 
i. 305). The salivary glands of the lice were dissected out and rubbed 
up in a minimum quantity of salt solution to which was added an equal 
volume of blood drawn up into a capillary tube from the pricked 
finger-tip. The blood and gland extract were mixed and placed in 
capillary tubes at 14° C. 
Expt. I. Blood + glands of 4 lice 
(2 tubes) coagulated after 40 min¬ 
utes. Control showed coagulation in 12 minutes. 
Expt. II. Blood + glands of 4 lice 
(2 tubes) coagulated in 60 minutes. Control showed coagulation in 15 minutes. 
SUMMARY AND CONCLUSIONS. 
The term Pediculosis denotes the pathological condition brought 
about by infestation with Pediculus humanus, either the head or the 
body or both of these being affected. Pediculosis may lead directly 
or indirectly to secondary infections of various kinds. P. humanus 
(corporis and capitis) has been shown to be the carrier of two im¬ 
portant diseases affecting man, namely typhus and relapsing fever. 
Typhus fever. 
The earlier evidence which is cited regarding the epidemiology of 
typhus, is all in accord with the discoveries proving that P. humanus 
conveys the disease and is the sole agent in its spread 1 . 
The geographical distribution of typhus is more restricted than that 
1 Zlatgoroff (in F. Kraus and T. Brugsch’s Spez. Pathol, u. Thera-p. inner. Krankh. 
xi. 682; cited by Eysell, iv. 1915, p. 238) is reported as stating that naked negroes on slave 
ships escaped typhus although they suffered much from other diseases. I have been 
unable to verify the reference, but as a piece of epidemiological evidence it is worth men¬ 
tioning. 
