640 NEISSERIA 



of the hind limbs, and dies in 1 to 2 days. Post mortem, there is a viscid, often haemor- 

 rhagic, fluid in both pleural cavities ; the lungs are hyperaemic in places and may be covered 

 with a false membrane ; the spleen is generally enlarged and congested. The organisms 

 are present in enormous numbers in the pus cells of the pleural exudate, and often, but not 

 always, in the blood and the spleen, in both of which situations they remain mostly extra- 

 cellular. 



Intraperitoneal injection with the same dose kills the mouse in 18 to 24 hours. Post 

 mortem, there is a small amount of sticky fluid in the peritoneal cavity, containing pus 

 cells ; the spleen is generally swollen and congested ; cocci are found in varying numbers 

 in the exudate, and in small numbers in the spleen and heart's blood. 



Guinea-pigs. — Weight for weight these animals are said to be somewhat more sus- 

 ceptible than mice (Rist and Paris 1904), but here again subcutaneous injection, even of 

 massive doses, fails to give rise to a general infection ; at most a small abscess is produced. 



Intrapleural injection of 1 ml. of a thick suspension of a young agar culture causes death 

 in 1 to 3 days. Post mortem, there is a thick exudate, poot' in fibrin, in both pleural cavities ; 

 the lungs are thickened and dark red ; the spleen is not enlarged. Cocci are found in the 

 exudate, but are generally absent from the spleen and heart's blood. 



Intraperitoneal injection causes death in 1 to 3 days. Post mortem, there is an exudate, 

 clear or turbid, in the peritoneal cavity ; on the rolled -up omentum and on the anterior 

 surface of the liver there is a deposit of fibrin and pus ; there are haemorrhages into the 

 mesentery, and into the visceral and parietal peritoneum ; the adrenals are vividly con- 

 gested and may be hsemorrhagic ; the pancreas and surrounding tissues are oedematous. 

 In the pleural cavities there is often an exudate of clear fluid ; the lymphatic glands are 

 swollen and congested. Cocci are found in moderate numbers in the peritoneal exudation, 

 but are absent from the blood and viscera. 



Sub-dural injection causes death in 20 to 24 hours ; post mortem, there is oedema and 

 congestion of the meninges, with pus at the site of injection ; there is a large amount of 

 clear fluid in the peritoneum, free from cocci (Albrecht and Ghon 1901). There is no multi- 

 phcation of organisms in the spinal fluid itself. 



Rabbits. — Subcutaneous, intrapleural, and intraperitoneal injections are generally 

 without effect. 



Intravenous injection with 1—4 ml. of a thick suspension of a young agar culture kills 

 the animals in 1 to 4 days. Post mortem, apart sometimes from a few areas of congestion 

 in the lungs, there is nothing abnormal to be found. No cocci are present in the blood 

 stream. 



Sub-dural injection into the skull occasionally causes death. Post mortem, there is 

 congestion of the meninges ; the cocci may be recovered in culture ( Weichselbaum 1887). 



Intracisternal injection by the sub-occipital route is stated to give rise to cerebrospinal 

 meningitis (Branham and Lillie 1932, Zdrodowski and Voronine 1932). To achieve success 

 virulent cultures and young rabbits (1,300-1,500 gm.) are desirable. The disease may 

 be acute and prove fatal in 24 hours, or sub-acute and cause death between the 2nd and 

 7th days. Clinically, rigidity of the neck, retraction of the head, spasticity, and sensitive- 

 ness to touch, or progressive paralysis may be noted. At necropsy the brain and cord 

 are markedly hypersemic and are covered with a thin layer of purulent exudate. The 

 cerebrospinal fluid may be almost clear, turbid, or frankly purulent. Meningococci can 

 be recovered from the spinal fluid and usually also from the blood. 



Dogs. — Weichselbaum (1887) stated that he had succeeded, by sub-dural injection, 

 in producing a pachy- and lep to- meningitis with acute encephalitis ; death occurred from 

 a few hours to the 12th day after inoculation. 



Monkeys. — Von Lingelsheim (1905) was apparently the first to reproduce the disease 

 in monkeys. After intraspinal injection one monkey became ill in 6 hours ; there was 

 retraction of the head and opisthotonos, and death took place in 30 hours. At necropsy 



