154 
On Rickettsia 
that the lice had fed on infected patients. In the first place Arkwright, 
Bacot and Duncan (1919), and the present writer found Rickettsia in three 
cases, and unquestionably these lice had never fed on any one infected with 
either trench fever or typhus. Moreover Topfer (1916) and Da Rocha Lima 
(1917) were both well aware of the possibility of their lice having been con¬ 
taminated and still came to the conclusion that there is a distinct parasite, 
Rickettsia jpediculi, occurring in the human louse. The results of the examina¬ 
tions of other species of lice also confirm the view that there may be a 
Rickettsia specific to the body-louse. 
(2) Observations on Rickettsia Quintana. 
Through the courtesy of Major-General Sir David Bruce, Chairman of the 
Trench Warfare Committee, a case of trench fever at the Mill End Hospital, 
Hampstead, was placed at my disposal. Unfortunately, this patient had only 
just recovered from an attack of roseola, but as his was the only case available, 
and he was suffering from an unmistakable attack of trench fever, it was decided 
to use him for obtaining Rickettsia quintana. Major Byam very kindly ar¬ 
ranged for two boxes of lice from the Quick Laboratory to be fed daily on 
this patient for a period of 14 days. These lice were then examined by various 
methods and 14 out of 22 were found to be infected with Rickettsia in large 
numbers. 
The faeces from both boxes, which previously had shown no sign of these 
organisms, were also examined and found to be infected. Although the 
amount of material was small, the appearance of the films made from infected 
lice was so strikingly different from any of the films made from uninfected 
lice that the presence of the Rickettsia was unmistakable. When seen singly 
or in very few numbers, it is possible to mistake them for staining artefacts, 
etc., but in the cases mentioned their definite shape and occurrence in clumps 
gave them a very characteristic appearance. However, as dried films stained 
with Giemsa are liable to produce artefacts, especially in the case of gut con¬ 
tents, some of the lice were fixed in various ways and afterwards sectioned 
and the sections stained. 
The most satisfactory results were obtained by fixing in sublimate alcohol 
containing 5 per cent, acetic acid and afterwards staining by Giemsa’s wet 
method, using acetone instead of alcohol for dehydrating. Other lice were 
fixed in Flemming’s solution, Bouin and Gilson, respectively, and afterwards 
stained by different methods. 
The aniline stains gave but indifferent results, as Rickettsia seem to have 
very little affinity for the ordinary staining reagents. When stained with iron 
haematoxylin it was very difficult to obtain any degree of differentiation that 
would clearly distinguish them from surrounding structures. When the sec¬ 
tions were under-differentiated it was possible to recognise the outlines of the 
Rickettsia , but the organisms always appeared slightly smaller than in sections 
stained with Giemsa. 
