THE FATE OF ARSENIC IN THE BODY. 647 



it remains to be seen whether the behaviour recorded in this case 

 is general or idiosyncratic. Provisionally we are inclined to con- 

 sider it abnormal, although it is possible that the intestinal mucosa 

 of the horse is more sensitive to arsenic than in the case of the 

 sheep, and that by stimulation of peristaltic movement the 

 arsenical contents of the first intestine are swept on into the 

 second, and opportunity for absorption thereby reduced. The 

 dose given (2 gm. may, in some cases, prove fatal) was some-, 

 what high for the horse, which in general appears to be more 

 susceptible to soluble arsenite than the sheep when dosage is 

 calculated per kilo body-weight. Probaljly the elimination of 

 smaller doses would follow more closely the channel shown for 

 the sheep. It may be mentioned, however, that a second experi- 

 ment was carried out upon a horse, using i gm. AsoOo as arsenite, 

 and that although the protocols are not sufficiently reliable for 

 detailed record (owing to breakage of the collecting- apparatus) 

 they point in the same direction and suggest a less perfect intes- 

 tinal absorption of soluble arsenic in the horse than in the sheep. 

 Whatever be the explanation in the individual cases recorded 

 here, the matter is worthy of further investigation. It should 

 be added, of course, that the rate of passage of arsenic into the 

 intestine is ])robably greater in the horse.' which has only one 

 stomach-compartment, than in the case of ruminants, such as 

 the sheep, with a four-compartment stomach system. 



Intravenous administration: Four experiments were carried 

 out — one tO' determine the rate of elimination of injected arsenic 

 in the horse and compare' it with the corresponding data pre- 

 viously obtained for the sheep (/. c, i, Table 9) ; and three to 

 determine and compare the distribution of injected arsenic over 

 the tissues. 



In the experiment designed to determine rate of elimination 

 after injection^ only 0.3 gm. AS0O3 as arsenite was administered, 

 but in spite of this the horse suffered irom shock, lay down and 

 damaged tli^ collecting apparatus, so that collection of urine was 

 not quantitative for the first 48 hours. The protocols of this ex- 

 ]:)eriment must therefore be left over for confirmation. Of the 

 three experiments showing the distribution over the tissues after 

 intravenous injection of arsenic, one was carried out on a cow. 

 one on a sheep, and one on a horse. The data for all three 

 cases are given in Table 6, in which the arsenic is expressed lin 

 milligrams per 100 grams of tissue, i.e., parts per hundred 

 thousand, and in milligrams total in the whole organ concerned. 

 The totals for blood and muscular tissue, given in brackets, are 

 approximately assessed on the assumption that the blood con- 

 stitutes about i/i2th of the body-weight and the total muscu- 

 lar tissues about half (lean animals). This serves to give a rough 

 notion of the absolute distrilnition over the bodv. 



