579 
1908-9.] The Pathogenesis of Micrococcus melitensis. 
or intraperitoneal infection during the suckling period, and at a later 
period of life to infection by feeding methods also. 
Morbid Anatomy. 
For the study of the morbid anatomy and morbid histology of M. 
melitensis infections, laboratory animals of course afford ample material, 
but the case mortality of M. melitensis septicaemia in man is extremely 
low. Writing in 1903, Hayat (38) could only collect details of 76 
autopsies, derived from Malta (67), Palermo (5), Netley (2), Naples (1), 
and Padua (1), for study. In Malta, during 1904, four, and in 1905 
nine, fatal cases were carefully investigated by the Mediterranean Fever 
Commission. Personally, whilst in Malta in 1906 I only had the opportunity 
of assisting at the post-mortem examination of one case of M. melitensis 
septicaemia that died in the Military Hospital, Valletta, and of being 
present at some twenty autopsies at the Civil Hospital, Floriana. The 
pathological apjeearances produced by M. melitensis septicaemia in fatal 
infections, based upon observations upon post-mortem examinations of 
lower animals and of man, I have already described elsewhere ( Lancet , 
June 20, 1908). 
Morbid Histology. 
Observations upon the morbid histology of M. melitensis septicaemia 
do not appear to have been numerous — chiefly, I imagine, because the 
changes that take place in the various organs and tissues are few, 
generally insignificant, and in no way to be distinguished from those 
noted in septicaemia due to any other micro-organism. This obtains no 
matter whether the material is collected from acute cases killed 
shortly after infection or from chronic cases where long intervals have 
elapsed between infection and death, or whether in lower animals or in 
man. I have carefully studied a large number of sections during the 
past seven or eight years, collected from many different mammals, and I 
must confess that up to the present I have been unable to demonstrate 
any extensive deviations from the normal — except in those cases where a 
laboratory inoculation has been planned to produce suppurative lesions 
such as subcutaneous abscess, suppurative peritonitis, or suppuration 
within the tunica vaginalis. Such lesions as have been observed are best 
considered in the order of the various organs, etc., adopted for the morbid 
anatomy. 
Heart , — Haemorrhages between the muscle fibres is the only noticeable 
feature : the myocardium itself appears norma]. 
