viii, B, 6 Schobl: Plague in Manila in 1912 419 



by the vaccination method, if the lower part of the abdomen 

 be chosen for inoculation. The reason for such a deviation from 

 the iindings in the rest of the guinea pigs may lie in the fact 

 that this animal was almost completely deprived of hair by a 

 skin disease. 



It is of importance to mention the skin lesions which were 

 found on the necks of the guinea pigs, particularly under the 

 chin. Besides small red spots which appeared to be fresh flea 

 bites, small, elevated, and fairly deep infiltrations partly covered 

 with moist scab were found in the skin under the chin. Other 

 animals showed changes usually found in the scarified skin of 

 guinea pigs after artificial inoculation with plague material. 

 The base of each cutaneous efflorescence was hsemorrhagic and 

 oedematous. 



A histological study of the tissues of these guinea pigs known 

 to be naturally infected by plague fleas showed the following 

 changes : 



The cervical bubo. — The enlarged lymphatic gland was surrounded with 

 a thickened capsule. Necrosis existed in the subcapsular part of the gland, 

 where it formed an almost continuous circular zone, leaving the central 

 part less changed. Smaller irregular necrotic foci were scattered throughout 

 the section. Polymorphonuclears in various stages of disintegration were 

 found throughout the section. 



The lungs. — Very few blood extravasations were present in the alveoli; 

 otherwise normal. 



The spleen. — The capsule was thin. There were subcapsular haemor- 

 rhages. The Malpighian bodies were somewhat enlarged, but of normal 

 structure. Throughout the parenchyma irregular multiple necrotic foci 

 were found, leaving but little of spleen tissue intact. Numerous polymor- 

 phonuclears which were present showed varying degrees of karyorrhexis. 



The kidneys. — The outline of the cells was indefinite; a few miliary 

 haemorrhages existed in the cortical part of the organ. 



The liver. — There was excessive congestion, fatty degeneration, and pig- 

 mentation of the cells. The capsule was slightly thickened. 



The skin. — The epithelium was missing in one place in the section, and 

 cellular infiltration extended from that place into the subepithelial layer 

 of the surrounding skin. The same kind of infiltration reached deep into 

 the skin, stripes of cellular infiltration penetrating into the tissue along the 

 muscle fibers. There was no direct connection between the cellular infiltra- 

 tion and the follicles of the hair. 



It may be well to describe in detail the time of death from 

 plague among these and the other animals in this outbreak, 

 as well as the time when the plague house was disinfected. 



The first animal (rat 1) having been inoculated on August 

 27, in the afternoon, died of plague within three days (August 

 30). The second animal (rat 2) died twenty-four hours later. 



