ORGAN AND BODY SYSTEMS 495 



gen rays or radium) may cause an inflammatory reaction characterized by 

 redness and edema of the mucosa. Several months or even years later, 

 these disturbances may be accompanied or followed by stenotic thicken- 

 ing and dyspnea, and in some cases by pneumonia and death. Many 

 examples of such reaction have been reported (Desjardins, 74). 



Salivary Glands. — After exposure to roentgen radiation the sub- 

 maxillary gland swells and the acini degenerate with loss of the lumen. 

 There is some infiltration of plasma cells and lymphocytes. The gland 

 cells become vacuolated, with granular protoplasm and abnormal nuclei. 

 Dilation of the capillaries may occur. These changes are less severe in 

 the parotid than in the submaxillary where regeneration first takes place 

 (28, 316). The secretion of saUva in the dog is reduced after heavy 

 radiation (37) but returns slowly to normal. The sensitivity of the 

 buccal mucosa is temporarily diminished, a response which probably 

 affects the sensation of taste. There is also a decrease in the ability of 

 the dog to control the muscle movements of mastication and swallowing, 

 an effect which may be due to the influence of the radiation of the periph- 

 eral motor nerves. This is practically the only reference to such an 

 effect and perhaps warrants further study. 



Desjardins (74) states that "there is no valid evidence that small 

 doses of radiation increase the functional activity of the salivary glands; 

 on the contrary, the evidence indicates that small doses have no effect, 

 but that strong doses interfere with their function and diminish any 

 secretion of saliva by causing metabolic inhibition and degeneration of 

 the specific epithelium of the glands. The degree of such action, as well 

 as its onset and duration, depend on the dosage, and the effect of irradia- 

 tion may be temporary or permanent for the same reason. The salivary 

 glands are exceptionally sensitive to irradiation. The reaction of the 

 glands thus induced may be early, late, or combined. Early reaction 

 occurs in a large percentage of cases in which the region of one or more 

 of the glands is irradiated, and consists of rapid swelling, with a sensa- 

 tion of heat and tension. The swelling begins a few hours after irradia- 

 tion and generally subsides spontaneously within 24 to 72 hr. Females 

 are twice as susceptible as males, and blondes more susceptible than 

 brunettes. The later reaction consists in dryness of the mouth which 

 appears from a few days to 2 to 3 weeks after irradiation of more or all of 

 the salivary glands, is most pronounced 2 to 4 weeks after exposure, 

 subsides slowly thereafter, and is due to decreased secretion of saliva. 

 Its severity and duration vary with the dosage. Both the early and late 

 reactions may occur in the same case." 



Esophagus. — There is relatively little information regarding the 

 effects of radiation on the esophagus because its position makes observa- 

 tion difficult. Probably its sensitivity is about the same as that of the 

 skin and mucous membranes of the mouth (99). Warren (368) noted 



