THE INFECTIOUS DISEASES. 277 



Calkins, from an independent study of the material furnished by 

 Councilman, is convinced of the protozoan nature of the organisms in 

 question and has formulated the stages of a complex life cycle. 1 



It is clear that final judgment upon the nature and significance of 

 these minute structures must be suspended until further experiments 

 upon suitable animals shall have furnished fuller biological data than are 

 yet at hand, which may sustain the evidence, still largely morphological, 

 on which these suggestive conclusions are based. 2 



SCARLET FEVER. (Scarlatina.) 



This is an infectious, readily communicable disease characterized by 

 a diffuse skin eruption, and frequently accompanied by inflammation, 

 either catarrhal. or croupous, or gangrenous, of the tonsils, pharynx, and 

 hirynx. Focal jiecroses. albuminous degeneration in the viscera, and 

 leucocytosis may occur. 



There m^y be acute hyperplasia or suppuration of the cervical lyniph- 

 nodes. There is very frequently an acute exjulative or an acute diffuse 

 nephritis. The snleen niay^be eiilarged. Broncho-pneumonia,, endocar- 

 ditis, and pericarditis may complicate the disease.. 



The exanthem or skin eruption in scarlatina ^ a simple dermatitis 

 as the result of which the papmse and subpapillary stratum become infil- 

 t rated with t^uid or leucocytes, or both, the leucocytes being gathered 

 especially about the blood-vessels. There may be small haemorrhages, 

 and the acute phase of the iiiflajjimatiou is followed by an increased pro- 

 duction of epithelium .and an exfoliation of the superficial layprg. These 

 lesions of the skin may be, excepting the haemorrhages, very slightly 

 marked after deat^T 



That the disease is _dne to some form of mi cro- organism there can be 

 no doubt. The exact nature of this organism is not yet known. The 

 acute nephritis and the marks of degeneration and focal necrosis so 

 often present appear to be due to some poison formed in the body during 

 the disease. 



Mallory 3 has described bodies in and between the epithelial cells of 

 the epidermis and free in the superficial lymph vessels and spaces of the 

 corium in scarlet fever which he believes to be protozoa and to bear an 

 etiological relationship to the disease. Most of these bodies are from 

 two to seven microns in diameter and stain with methylene blue. A 

 series of forms are found, including rosettes, which are said ( to resemble 

 the series in the asexual development of the malarial parasite. Further 

 studies will be required to establish the protozoan nature as well as the 

 significance of these structures. 



One of the most marked features of the disease is the predisposition 



1 Calkins, "Life History of Cytoryctes Varioloe," ref above, p. 136 



2 Consult for general bibliography Freeman, article on vaccination in "Cyclopedia 



of the Diseases of Children," vol. v., suppl,. p. 263; or Moore, in "Twentieth Century 



Practice," vol. xiii. 



3 Mallory, Jour, of Med. Res., vol. x. 1904, p. 483. 



