Symptoms. 293 



observed in the throat, while on the buccal mucous membrane 

 small hemorrhages may sometimes be found. Some patients 

 periodically shake their heads, at the same time giving a pecu- 

 liar sound, and expelling saliva from nose and mouth. In rare 

 cases profuse diarrhea is observed, the droppings being dirty 

 gray or greenish, fluid and exceptionally red colored. 



Towards the end of the disease the affected birds hold their 

 heads turned toward the back, their respiration is very labored, 

 and finally paralysis appears, which progresses from the ex- 

 tremities to the head. 



In artificial infection the body temperature commences to 

 rise after 12 hours, and later may exceed 44° C. At the approach 

 of death however it drops rapidly, even to 30° (Fig. 53). 



Maggiora & Valenti describe a diphtheroid form of the disease, 

 in which a muco-fibrinous exudate forms on the surface of the swollen, 

 bright red mucous membrane of the mouth, throat and nose. 



The same authors observed in several affected chickens peculiar 

 nervous symptoms in addition to irregularity in walk, and symptoms 

 of paralysis, which were manifested by moving the head in a circle ; 

 Centanni has seen disturbances in the equilibrium, lasting for 

 weeks in pigeons which were inoculated with blood, especially turning 

 the head, moving in a circle, and a desire to turn the body around 

 its long or transverse axis. The examination revealed as the cause 

 of these disturbances an exudative inflammation of the membranous, 

 semi-circular canals of the organs of hearing (semicirculitis specifica). 

 Calamida has also observed the turning of the head backwards, and 

 besides, shortly before death, attacks of delirium which somewhat re- 

 semble rabies, the birds jumping very high during these attacks. 



In artificially infected geese the disease runs a slower course (an 

 average of 7 days), and as a rule under manifestations of striking 

 nervous symptoms, which are indicated by tonic-clonic spasms, involun- 

 tary movements, fluttering of the wings, spasmodic extension of the 

 neck, increased reflex irritability, etc. At the approach of death the 

 symptoms pass into paralysis. The blood of these birds, as well as of 

 artificially infected pigeons, is infectious only at the beginning of 

 the affection, while later the virus disappears entirely. The brain and 

 spinal cord, on the other hand, remain highly infective even after 

 death (Kleine). This may be explained by the fact that the virus 

 emigrates from the blood into the nervous cellular elements, and 

 becomes anchored there as a result of its specific affinity for the cell 

 plasma. This would correspond with the histological findings (prolifera- 

 tion of round cells, the above-mentioned bodies) as well as witli the 

 findings of Landsteiner, according to which the virus is, in contrast to 

 bacteria, quickly destroyed by a 1% saponin solution. 



Kleine observed atrophic areas in the eye ground of a chicken, 

 and various kinds of chorio-retinitic areas in geese. 



Course. The course of the disease is 2 to 4 days as a rule 

 with the exception of the very rapidly terminating cases, and 

 only exceptionally it extends to 7 or 8 days. The termination 

 appears to be fatal in the great majority of cases. 



' Diagnosis. The disease greatly resembles chicken cholera 

 in its course, and is only distinguished from it in that in this 



