280 DIGESTION. 



taken ; this, however, is by no means the case. In my latter inves- 

 tigations regarding the composition of the blood in different vessels, 

 I have on several occasions (after feeding the animal abundantly 

 on bran) found the serum of the portal blood even far poorer in 

 salts than the serum obtained from the blood of the arteries or of 

 the vena cava ; thus, for instance, in one case the serum of the 

 arterial blood contained 0'853-J, that of the blood of the vena cava 

 0'887, and that of trie portal vein 0'52l of salts; these num- 

 bers calculated in relation to the solid residue of the serum in each 

 case give a similar result ; in the solid residue of the serum of arte- 

 rial blood the salts amount to 8'392 -, and in that of the vena cava 

 to 8*501^5 while in that of the portal vein they only reach 4' 895. 

 Even in this portal blood, which was so poor in salts, not a trace 

 of sugar could be found. 



It has been already mentioned (p. 234) that sugar, even when 

 injected with one or two equivalents of alkaline carbonate, still 

 passes into the urine. 



Since, therefore, it appears probable that only little sugar is 

 resorbed by the blood-vessels of the intestine, the question sug- 

 gests itself, whether the sugar is not probably taken up in so much 

 the larger quantity by the lacteals. But my earlier observations, 

 as well as those recently made on the chyle of the above-mentioned 

 three horses, are opposed to this supposition. It has been already 

 mentioned (vol. ii, p. 286) that it was only after the use of highly 

 amylaceous fodder that I could detect small quantities of sugar in 

 the chyle of horses, and in my latest experiments with the three 

 horses I arrived at no result which would favour the view that the 

 sugar is absorbed by the lacteals. If we assume that the average 

 quantity of chyle which is poured into the subclavian vein of the 

 horse in 24 hours amounts to 50 kilogrammes [110'23lbs.], as 

 might be inferred from what has been already stated (see vol. ii, 

 p. 292), then in these cases, when digestion was constantly going 

 on, 37'4 grammes of chyle must have passed through the thoracic 

 duct in one minute. The quantities of chyle which I obtained 

 from the thoracic duct in the horses A, B, and C, was 22-567, 

 18-184, and 25 '6 16 grammes respectively. Now, according to 

 our calculations, we see that about 1 gramme of sugar was resorbed 

 by each horse in 1 minute. If, therefore, the sugar has neither 

 been taken up by the blood-vessels, nor has been previously meta- 

 morphosed in the intestine, there must be about 1 gramme of 

 sugar in 37'4 grammes of chyle ; but if only O'l of a gramme 

 of sugar were contained in this quantity of chyle, it would readily 



