LATHYRISMUS 



197 



was doughy in consistence, alkaline, insoluble in water, slightly 

 soluble in ether, soluble in chloroform, and which on evaporation 

 formed needles; but he did not perform any experiments with 

 the substance, the action of which is therefore unknown. It is 

 believed by some that Lathyrus is not poisonous unless the seeds 

 are decomposed or contain some parasitic growth, while others 

 hold that the symptoms are not due to Lathyrus at all, but to 

 Agrostemma githago (the corn-cockle) or Lolium temulentum (the 

 darnel). In 1883 Astier separated out an alkaloid, lathyrin, which 

 Stockman in 1917 showed to be the poisonous principle, which is 

 present in only small amount and only in the seed itself. 



Animals are by no means immune from the baneful effects of the 

 plants, for ducks become paralyzed and may die after eating the 

 seeds; while pigs and horses also suffer, the latter showing acute or 

 chronic symptoms which are said more or less to correspond to 

 lathyrismus. On the other hand, bullocks and buffaloes are con- 

 sidered to be immune. 



The great predisposing cause in man is scarcity of food, whether 

 due to famine or poverty, both of which compel the unfortunate 

 people to eat vetches instead of ordinary food. If the disease is 

 brought about by famine, it may assume epidemic proportions; if 

 by poverty, it may be simply endemic. Young people are more 

 liable to be poisoned than old persons, and men more than women, 

 perhaps because they eat more food. 



Morbid Anatomy. — ^The pathology and morbid anatomy need 

 investigation. When this is done, it is probable that some lesion of the 

 pyramidal tracts^ — i.e., of the upper motor neurones — will be found. 



Symptomatology. — The incubation period is not known, and the 

 disease comes on so insidiously that the patient often attributes it 

 to a chill which he may have experienced a day or so previously. 



Prodromata are often said to be absent, though it is more prob- 

 able that digestive disturbances, colicky pains, and diarrhoea do 

 occur, but pass unnoticed. 



One of the first symptoms to arise is pain in the back and weak- 

 ness in the legs, which increase until symptoms of spastic paraplegia 

 appear. The patient now complains of girdle sensations, and walks 

 with difficulty . The gait is characteristic, for the feet are turned 

 slightly inwards, and are dragged or raised with difficulty from the 

 ground. The joints appear so weak that it is difficult to proceed 

 any distance without falling, while the body has a peculiar up and 

 down motion. There is no ataxy, and no vasomotor phenomena, 

 but the legs waste very much. The arms are not, as a rule, in- 

 volved, though the hands may tremble. The superficial and deep 

 reflexes are increased, and ankle clonus is present. The electrical 

 excitability of the affected muscles is diminished, but the reaction 

 of degeneration is absent. Incontinence of urine and impotence 

 are early and common symptoms. The mind is unaffected. 



The disease does not itself end fatally, but a definite improve- 

 ment is seldom seen except in incipient cases. 



