76 Miscellaneous, 



Whilst staying at Messina in the autumn of 1853, Troschel 

 purchased two specimens of Doliuin from the fishermen, and on 

 returning to his residence he prepared to put them in spirits. For 

 this purpose he broke the shell of one of them in the region of the 

 spire, when the animal elongated itself outwards, pushing out 

 its proboscis as far as it could, and moving it about in all directions 

 with a threatening aspect. Troschel then wished to seize the ex- 

 tremity of this proboscis, which was dilated into a trumpet, in order 

 to examine it more closely, when the animal suddenly projected a 

 large stream of a transparent liquid, which fell upon the floor at a 

 distance of several feet. A moment afterwards the calcareous slabs 

 with which the floor was paved were covered with froth, the liquid 

 evidently containing an acid which produced effervescence with car- 

 bonate of lime. J. Miiller, who was then at Messina, was a witness 

 of this phsenomenon. 



The experiment was repeated with the second Dolium, but this 

 time the fluid was received in a glass. It was colourless and not 

 frothy, but dissolved carbonate of lime rapidly wdtli effervescence. 

 Troschel afterwards collected a great number of specimens, which 

 enabled him to obtain the acid liquid in great abundance. A single 

 individual furnished as much as three ounces. The pressure of the 

 finger upon the region corresponding with the salivary glands was 

 sufficient to cause the expulsion of the saliva. 



In April 1854, after his return to Bonn, Troschel forwarded a 

 bottle of this singular saliva to Dr. Boedeker at Gottingen, for 

 analysis. The liquid did not present the least trace of decomposition 

 or fermentation, and had not given rise to any formation of mould, 

 although it had been collected six months before. It was as clear 

 as water, possessed a very acid taste, and boiling did not produce 

 any precipitate in it, even when the free acid had previously been 

 neutralized by soda. Consequently it did not contain any albumen. 

 The quantity of organic substances contained in this liquid was found 

 to be excessively minute. No trace of urea, or of sugar, was found 

 in it ; on the other hand, the analysis proved the existence in it of 

 an abundance of muriatic and sulphuric acids, and of sulphates of 

 magnesia, potash, and soda. It gave the following results : — 



Free anhydrous muriatic acid (HCl) 0*4 



Free hydrated sulphuric acid (HO, SO^) (corresponding to 



2*2 per cent, of anhydrous sulphuric acid) 2*7 



Anhydrous sulphuric acid combined with bases (neutral salts). 1*4 

 Magnesia, potash, soda, a little ammonia, very little lime, and 



organic matters, forming in all 1*6 



Water 93*9 



1000 



The existence of such a liquid in the body of an animal is of high 

 interest. The zoologist and the physiologist must inquire what can 

 be the object of such a secretion, if it be not a purely excretory 

 substance. The chemist must join the physiologist in attempting 



