PLANKTON 



49 



when convulsions came on, with the head and neck drawn back by rigid 

 spasm which subsided before death." Similar manifestations have been 

 reported from Alberta, 269 Manitoba, 262 North Dakota, 266 Minnesota, 254 

 Ontario, 268 and South Africa. 258 " 260 In several of these, the animals also 

 exhibited extreme photosensitivity, 266 with severe blistering of the 

 skin, 258 " 260 and also jaundice. 258 



Fitch 254 tested laboratory animals on the Microcystis and Anabaena 

 which had killed cattle in Minnesota. The characteristic symptoms in 

 guinea pigs included restlessness, incontinence, deep breathing, sneezing, 

 coughing, salivation, lacrimation, weakness in the hind quarters, clonic 

 spasms, and death. Rabbits presented the same picture plus opisthotonus. 

 Pigeons also developed opisthotonus, as well as rapid blinking and 

 swallowing. 



Mason and Wheeler 270 injected Microcystis aeruginosa extract into 

 mice, rats, guinea pigs, and cats. After a latent period of 20-180 minutes, 

 there appeared pallor, hypotension, tachycardia, hypothermia, hyper- 

 glycemia, respiratory difficulty, and death. Steyn 258 - 260 in South Africa 

 reported general paralysis or strychnine-like convulsions following con- 

 sumption of large quantities of Microcystis by cows; smaller amounts re- 

 sulted in constipation, drop in milk yield, generalized weakness, and severe 

 photosensitivity of the skin. If the animals survived longer, many devel- 

 oped jaundice and ascites. Some of Steyn' s laboratory animals manifested 

 symptoms after simply being drenched with the contaminated water. 

 Smit 271 injected or fed Microcystis to rabbits. In acute cases, the animals 

 developed anemia, restlessness, dyspnea, progressive paralysis, coma, and 

 death within one-half to four hours. In chronic cases, the outstanding 

 finding was cirrhosis of the liver, with restlessness, atonia, and ascites. 

 McLeod and Bondar 262 in Manitoba found that Microcystis administered 

 to rats and mice caused a loss of equilibrium and progressive paralysis; 

 later there were clonic muscular spasms, dyspnea, and cyanosis, then death 

 within twenty hours. 



The pathological findings in phytoplanktonic intoxications have been 

 most interesting. Autopsies made in 1930 and 1933 in Minnesota showed 

 "no gross pathology" 254 ; cultures, smears, guinea-pig inoculations, and 

 tests for copper and cyanide were also negative. On the other hand, 

 Mason and Wheeler, 270 after injecting Microcystis extracts, observed mark- 

 edly congested livers and dilated right hearts, but little generalized venous 

 congestion. Their terminal clinical findings included severe anemia and 

 reduction in total serum proteins. Small amounts of the toxic extract 



