548 POISONS : THEIR EFFECTS AND DETECTION. [§§ 726 , J2J. 
§ 726. Pathological Changes. —Robert and Kiissner observed that 
when oxalate of soda was subcutaneously injected into animals, there 
was often abscess, and even gangrene, at the seat of the injection. If 
the poison were injected into the peritoneal cavity, death was so rapid 
as to leave little time for any coarse lesions to manifest themselves. 
They were not able to observe a cherry-red colour of the blood, nor did 
they find oxalate of lime crystals in the lung capillaries ; there were 
often embolic processes in the lung, but nothing typical. They came, 
therefore, to the conclusion that the state of the kidneys and the urine 
was the only typical sign. The kidneys were dark, full of blood, but did 
not show any microscopic haemorrhages. Twelve hours after taking 
the poison there is observed in the cortical substance a fine striping 
corresponding to the canaliculi; in certain cases the whole boundary 
layer is coloured white. If the poisoning lasts a longer time, the 
kidneys become less blood-rich, and show the described white striping 
very beautifully ; this change persists several weeks. The cause of this 
strange appearance is at once revealed by a microscopical examination ; 
it is due to a deposition of oxalate of lime ; no crystals are met with in 
the glomerules. Both by the microscope and by chemical means it may 
be shown that the content of the kidney in oxalates is large. 1 So far 
as the tissues generally are concerned, free oxalic acid is not likely to 
be met with ; there is always present sufficient lime to form lime oxalate. 
The urine was always albuminous and contained a reducing substance, 
which vanished about the second day after the dose. Hyaline casts and 
deposits of oxalates in the urine never failed. 2 
§ 727. Observations of the pathological effects of the oxalates on 
man have been confined to cases of death from the corrosive substances 
mentioned, and hence the intestinal tract has been profoundly affected. 
In the museum of St Thomas’s Hospital is a good example of the effects 
produced. The case was that of a woman who had taken a large, un¬ 
known quantity of oxalic acid, and was brought to the hospital dead. 
The mucous membrane of the gullet is much corrugated and divided 
into numerous parallel grooves, these again by little transverse grooves, 
so that the intersection of the two systems makes a sort of raised 
pattern. It is noted that in the recent state the mucous membrane 
could be removed in flakes ; in the upper part it was whitish, in the 
lower slate-coloured. The stomach has a large perforation, but placing 
1 The important fact of the oxalate-content of kidneys and urine, and the expul¬ 
sion of casts, was first observed by Mitscherlich in 1854. He noticed in a rabbit, to 
which had been given 7-5 grms. of oxalic acid, and which had died in thirteen 
minutes, “ renes paululum magis sanguine replete videbantur, in urina multa corpora 
inveniebantur, qua? tubulos Bellenianos explese videntur (De cicidi acctici, oxalici, 
tartarici, citrici, formici, et boracici, etc., Berlin). 
2 Rabuteau has discovered by experiment that even the oxalates of iron and 
copper are decomposed and separated by the kidneys. Gaz. Med. de Paris, 1874. 
