39 



Though no special organs are present for this purpose, the 

 perivisceral fluid is by no means stagnant and without currents. 

 The whole peritoneum is ciliated and these ciha of course cause 

 currents. That such ciliar currents can take care very well of 

 the distribution of dissolved substances, was shown by W id- 

 mark 132) for jelly-fishes in a detailed investigation. 



A ninhydrin test for amino-acids in the perivisceral fluid 

 invariably has a negative result in animals which have been in 

 the aquarium for more than a day. In some very fresh specimens 

 one occasionally -gets a slight 'pinky color ; in one starfish that 

 was caught while it was eating a Littorina, a strongly positive 

 result was obtained. Fehlingh's test is, as Cohnheim found 

 already, always negative, no monoses appear to be present. 

 A biuret test invariably gives negative evidence; neither the 

 violet color which indicates the presence of proteins, nor the 

 pink of peptones was ever seen. This proves that no proteins 

 are present in the filtered perivisceral fluid, as moreover a nega- 

 tive xanthoproteic reaction showed. This result is in contra- 

 diction with the assumption of many of the older investigators : 

 Cuenot 23) '), Semper 120) Geddes 42), Mourson and 

 Schlagdenhauffen 90) and Williams (Philos. Transact. 

 1852). No free fat is present; the Ph is in most cases the same 

 as that of sea-water (see chapter 24). Its specific gravity is also 

 the same as that of sea-water (Geddes). An analysis of the 

 ash compounds has been given bij Griffiths 49) and by 

 Mourson and Schlagdenhauffen 90). Griffiths how- 

 ever finds 0.042—0.049 "/o fibrin (!) and Mourson and 

 Schlagdenhauffen 0.010 — 0.013 "/q urea, both of which are 

 now known to be absent. More COj and less O2 is of course 

 found in the perivisceral fluid as compared to the sea water (M.6S.) 



As far as the waste constituents are concerned, no more am- 

 monia is found in the perivisceral fluid than in sea water. 

 Nessler's reagent gives a white precipitate of Ca-hydroxyde 

 with sea water. If however a trace of ammonium sulfate has 

 been added, the precipitate has a deep orange color. 



The precipitate is just as pure white in the perivisceral fluid 

 as in sea water. No creatinine is present as Jaffe's test, which 

 demonstrates the presence of this substance even in a dilution 

 of 1 : 5000, is negative. 



Thus far it seems that none of the constituents which are 

 present in most bloods, occur here. One of the waste consti- 

 tuents however is present, i. e. uric acid. Folin-Wu's phos- 

 photungstic-phosphomolybdic acid gives a blue coloration in the 

 alcalinised liquid. The intensity of this color is very different 

 in different cases, but it always occurs. It is not due to poly- 

 phenoles, since ether extraction does not take away the color. 



This author changed his opinion later on, 



