340 Dr. J. W. Pickering. The Chemical and Physiological 



solution. I may here mention that salicylsulphonic acid does not 

 precipitate disintegration products of proteids like leucine, tyrosine, 

 xanthine, or hypoxanthine. 



All the precipitates cited above give the colour reactions charac- 

 teristic of the original substance. 



If the original solution is saturated with either magnesium sul- 

 phate, ammonium sulphate, or sodium, chloride, the whole of the 

 colloid rises to the surface of the liquid, and may be skimmed off. 

 On placing this scum in an excess of distilled water, it rapidly 

 redissolves, forming a pale yellow opalescent solution, which gives 

 all the chemical reactions characteristic of the original substance. 

 If the amount of neutral salt be insufficient to produce precipita- 

 tion, the passage through the liquid of a current of carbon dioxide 

 or of sulphur dioxide will effect the same result. Neither of these 

 gases will, however, cause precipitation in the entire absence of salts. 



The following experiments illustrate the results produced by the 

 intravenous injection of this substance into dogs, rabbits, and cats. 

 The procedure adopted was identical with that described in the 

 previous papers published by Professor Halliburton and myself,* on 

 the intravascular injection of Grimaux's colloids. In all cases the 

 animal was ana3sthetised by a mixture of chloroform and ether, an 

 excess of the latter substance being used when the subjects were dogs. 



'Experiment 1. Fox terrier (weight 27 Ibs. 10 oz.) ; 25 c.c. of a 

 0*75 per cent, solution of the colloid a was injected, and proved 

 fatal. Pronounced exophthalmos and dilatation of the pupils, and 

 typical stretching movements were observed. 



Post-mortem examination made immediately after death revealed 

 pronounced clots in the jugular vein, inferior vena cava, and portal 

 vein, and a slight clot in the left ventricle and in the pulmonary 

 artery. 



Experiment 2. Large black cat (weight 9 Ibs. 6 oz.) ; 40 c.c. of the 

 colloid proved fatal, with similar symptoms as above. Immediate 

 post-mortem examination showed pronounced clots in the left ventricle, 

 right auricle, inferior vena cava, portal, and jugular veins. The 

 remainder of the blood was fluid, but coagulated very rapidly after 

 withdrawal. 



Experiment 3. Black rabbit ; 38 c.c. of the same substance pro- 

 duced a similar result. 



Experiment 4. Albino rabbit ; 42 c.c. proved fatal. Death was 

 accompanied by pronounced exophthalmos and dilatation of the 

 pupils and stretching movements of the limbs. Post-mortem exami- 

 nation showed the blood throughout the vessels to be fluid. It, how- 

 ever, rapidly coagulated after withdrawal from the vessels, and the 

 coagulability of samples of the blood taken from, the carotids during 



Op. cit. 



