324 COLLOIDS IN BIOLOGY AND MEDICINE 



On the basis of M. H. FISCHER'S investigations, the latter view 

 must be regarded as correct. If a dilute salt solution is placed in 

 the peritoneal cavity of a normal living or a dead guinea pig, it will 

 soon be absorbed. More concentrated salt solutions as well as 

 solutions of the salts which cause loss of water in the case of fibrin, 

 gelatin, etc. (e.g., sodium sulphate, citrate and tartrate) are either 

 not absorbed at all or even increase their volume inasmuch as fluid 

 enters the peritoneal cavity from the body. If albumin solution 

 is injected into the peritoneal cavity, very little will be absorbed 

 within an hour. The tissues about the peritoneal cavity behave in 

 this case just as does every dead colloid that is capable of swelling, 

 and there is no difference between intestine and peritoneal cavity. 

 The results are not so uniform when glycerin or sugar solution are 

 injected into the peritoneal cavity. Though these have a very slight 

 influence on the swelling of fibrin, they cause an entrance of fluid 

 into the peritoneal cavity. Evidently they cause, as they do in the 

 intestine, an irritation (see p. 323). 



The investigations of this question are not completed as the re- 

 searches of L. ASHER* have shown. 



A great number of marine animals have a body surface which is 

 permeable for water though not for salts. Corals, echinoderms, 

 holothurians, etc., swell in dilute, and shrink in concentrated sea 

 water. [A practical application is the " ripening " of oysters." Tr.] 

 The same fact obtains for many fresh-water animals, especially am- 

 phibia, worms and snails. Frogs never take water through their 

 mouths, they " drink through their skins." In the case of these fresh 

 water animals there occurs no swelling during life for the kidney 

 excretes the excess of water. The skin is also permeable for lipoid- 

 soluble substances. The skin of warm-blooded animals is different 

 from that of cold-blooded animals in that it is almost impermeable 

 for water and allows only lipoid-soluble substances to pass through 

 (W. FILEHNE* and A. SCHWENKENBECHER*). 



From what has been said, it is evident that a whole group of 

 factors such as rate of diffusion, swelling, osmotic pressure, play a 

 part in absorption and we shall observe the same for secretion 

 and that there are many gaps in the experimental data which sup- 

 port these views. 



The undoubtedly active role of adsorption has not been touched 

 upon; and it is possible that the negative phase of the blood pul- 

 sations may have certain importance through its suction. Some 

 phenomena regarded as filtrations, for which the pressure in the in- 

 testines seems somewhat too slight, may be explained by a pulsating 

 loss of swelling (dehydration). The alcohol question received a new 



