lO QUATERCENTENARY STUDIES IN PATHOLOGY 



the shaved skin of a guinea-pig, which died in six days of typical plague. 

 Although the animal died of undoubted plague, yet from the heart-blood 

 a pure growth was obtained of numerous colonies, conforming in every 

 way to the type of B. enteritidis. 



MacConkey gives a similar instance in the case of guinea-pigs dying 

 from experimental inoculations of B. typhosus and B. mallei. 



V. — Mus decumanus brought to the laboratory dead. 



Naked-eye appearances — 



Spleen enlarged and congested ; liver pale, and covered with fine 

 necrotic areas ; some pleural effusion ; lungs ha^morrhagic. 

 Microscopically — 



Spleen — many bipolar bacilli. 



Liver — a few bipolar bacilli. 



Heart-blood — no bacilli seen. 

 Animal test — 



The spleen and liver were rubbed into a shaved area of skin of a 

 guinea-pig weighing 280 grammes. At the end of a week it was 

 chloroformed to death. Examination showed a small right inguinal 

 gland, with glairy contents, slight cutaneous reaction, and a nodule in 

 the spleen the size of a millet seed. Cultures from heart-blood were 

 sterile, but from the gland and spleen nodule the usual organism was 

 obtained. 



From the foregoing details, it may be asserted that organisms of the 

 " Gsertner " type occasionally occur in rats, and that if the cutaneous 

 method in guinea-pigs be employed for purposes of diagnosis, an 

 infection by this organism may result. Confusion from this cause may 

 easily be avoided if the possibility of such an infection be remembered. 



Additional emphasis may be given to the fact that the organism may 

 be recovered in pure culture from the heart-blood of a guinea-pig with 

 well-marked lesions produced by another bacillus. Error in diagnosis 

 might, in some cases, possibly result if this circumstance were overlooked. 



It only remains, in the concluding part of this paper, to compare the 

 lesions found in diseases caused by other Gaertner-like organisms with 

 those already described. These are, viz. — the bacillus of swine-pest, 



(296) 



