228 SYMPTOMS AND MORBID APPEARANCES 



subsequently torpidity of the bowels. These symptoms 

 simulate those of gastric distension in horses and impaction 

 of the third stomach of cattle disorders for which lead- 

 poisoning has been mistaken. Distinctive features shortly, 

 however, present themselves. Anaemia is a marked feature, 

 probably because of the destruction of red cells, but partly 

 from malnutrition. Along the margin of the gums appears a 

 grey or blue line of lead deposited in the connective tissue, 

 blackened by hydrogen sulphide present in the mouth, or by 

 sulphur in the food. Colic and constipation are not so 

 invariably present in the lower animals as in human patients. 

 The extensor muscles of the limbs are cramped and paralysed 

 earlier and more seriously than the flexors. The affected 

 muscles gradually waste. The cause of the paralysis of 

 muscles is generally thought to be peripheral neuritis, and 

 experimentally lead has often been found to cause nerve 

 degeneration in animals. In some cases, however, degenera- 

 tion of motor areas in the spinal cord has been found. In 

 cattle lead-poisoning occasionally proves a cause of abortion. 

 Amaurosis and amblyopia are not infrequently caused 

 by lead, probably inducing optic neuritis. In animals, 

 too, chorea, convulsions, and delirium are easily set up by 

 lead-poisoning, and these symptoms often arise with great 

 suddenness. They appear to be due to a direct action on 

 the cells of the cerebrum. 



Shenton, a veterinary surgeon practising in Derbyshire, 

 in 1861, had eleven horses poisoned, and several cattle, and 

 thus described the conditions which came under his observa- 

 tion : ' There was a rough, staring coat, a tucked-up 

 appearance of the abdomen, and a slightly accelerated pulse ; 

 in fact, symptoms of febrile excitement, which usually, 

 however, passed away in about a week. About this time 

 large quantities of grey-coloured mucus were discharged 

 from the nostrils, and saliva from the mouth ; but at no 

 time was there any enlargement of the submaxillary, 

 lymphatic, or salivary glands. Neither was there constipa- 

 tion of the bowels, which appears to be nearly always present 

 in lead-poisoning in man./ Fits and partial paralysis came 

 on at intervals, and when the animals got down they often 

 struggled, for a long time ineffectually, to get up again. 



