ABSORPTION FROM CONNECTIVE TISSUES. 303 
were able to absorb fluids as well as solids in Bne suspension or solution. 
A number of reasons for this conclusion are given by Johannes Muller, 
and I may quote some of these as an example of the arguments by 
which older anatomists, such as Hunter and Hewson, had come to hold 
this opinion. In the first place, the lymphatics often become painful, 
red streaks appear in their course, and the neighbouring lympjhatic 
glands become swollen after the application by friction of irritating 
matters to the skin. Mascagni asserted that, in animals which died 
from pulmonary or abdominal haemorrhage, the lymphatics of the pleura 
and peritoneum were rilled with blood ( Muller discredits this assertion as 
"extravagant"). Mascagni and Soemmering observed bile in the 
lymphatics coming from the liver, in cases where the bile ducts were 
obstructed. Tiedemann and Gmelin, 1 after tying the ductus choledo- 
chus in dogs, found the lymphatics of the liver tilled with a fluid of a deep 
yellow colour. The lymphatic glands through which these lymphatics 
passed were yellow, and the yellow fluid taken from the thoracic duct con- 
tained biliary constituents. The effect of this and similar evidence on the 
minds of the anatomists in Hunter's time was rather curious. Since 
nature had provided a system — the lymphatics — on purpose to serve 
the office of absorption, it was considered in the highest degree 
improbable that this office would also be carried out by the veins, and 
"William and John Hunter, as the result of experiments on absorption 
from the intestines, concluded that the veins take no part in absorption. 
To this view of exclusive power of absorption possessed by the 
lymphatics, it was objected that animals exist which possess neither 
lacteals nor lymphatics. It was therefore regarded as a brilliant victory 
for the hypothesis, when Hewson demonstrated the existence of lacteal 
and lymphatic vessels in birds, reptiles, and fishes. 
Subsequent researches, especially by Magendie, 2 have shown, how- 
ever, that absorption from all parts of the body can be effected by 
blood vessels as well as by lymphatics. Magendie's researches have 
been continued and extended of late years by Ascher 3 in the case of 
the connective tissues of the lower limbs, by Tubby and myself 4 in the 
case of the pleural and peritoneal cavities. We found, for example, 
that, after injecting methylene-blue or indigo-carmine into the pleura, 
the dye-stuff appeared in the urine within five minutes, whereas the 
lymph presented no trace of blue for another twenty minutes, or even 
two "hours. It is evident that in this case the dye must have been 
taken up by the blood vessels and not by the lymphatics, and that 
this vascular absorption takes place with extreme rapidity. In a later 
series of experiments, Leathes 5 has shown that, after introduction of 
various salt solutions into the serous cavities, an interchange of con- 
stituents takes place directly between the blood and the injected fluid, 
so that the latter' in a very short time becomes isotonic with the blood 
plasma. Now, in this mode of absorption by the blood vessels the so- 
called absorption really consists in an interchange between blood and 
extravascular fluids — an interchange apparently dependent entirely 
upon processes of diffusion between these two fluids. So long as any 
1 Quoted by Muller (Baly's translation, vol. i. p. 242). 
2 Precis elementaire de physiologie," Paris, 1836. 
3 Ztschr.f. Biol, Miinctien, 1893, Bd. xxix. S. 247. 
4 Jour/i. Physiol., Cambridge and London, 1894, vol. xvi. p. 140. 
5 Ibid,, 1895, vol. xviii. p. 106. 
