HOST RESPONSE TO ANTIGENIC ACTION 455 



coccal protein was merely a concomitant of immunity without hav- 

 ing any significant part in the immunological mechanism. 



Sharp and Blake (1930) 1260 differed with the conclusions of 

 Mackenzie and maintained that in rabbits a fairly close parallel- 

 ism exists between cutaneous and pulmonary hypersensitiveness to 

 pneumococcal autolysate, and that the inflammatory response of 

 pulmonary tissue, resulting from contact with autolysate, depends 

 on the allergic state of the animal rather than on inherently in- 

 jurious substances in the autolysate. Sharp and Blake interpreted 

 their observations as being in harmony with the theory that al- 

 lergy may play a part in the pathogenesis of pneumococcal pneu- 

 monia in man. 



Julianelle and Rhoades (1932), 696 in a study of the reaction of 

 the lungs of rabbits to infection caused by intravenous injections 

 of Pneumococcus, found that reactions occurred irregularly in the 

 lung, and that in the lungs in which reactions did occur, the his- 

 tological changes were no different in normal rabbits from the 

 changes in rabbits made resistant by previous intravenous or in- 

 tracutaneous injections of pneumococci. The authors concluded 

 that the experiments afforded no evidence to support the view that 

 the lesions in the lungs of rabbits, following the intravenous injec- 

 tion of pneumococci, were modified by any previous state of sensi- 

 tivity. 



Dermal Allergy 



SKIN REACTIONS IN EXPERIMENTAL. ANIMALS 



The development of an allergic condition of the skin in guinea 

 pigs following the intracutaneous injection of an alkaline extract 

 of pneumococci occurred in experiments described by Mackenzie 

 and Woo (1925). 845 About two-thirds of the animals so treated 

 acquired cutaneous hypersensitivity but, upon the continuance of 

 the injections, the capacity of the dermal tissues to react ceased. 

 Neither the animals manifesting skin allergy nor those that failed 

 to develop this type of hypersensitiveness showed any significant 



