284 RAMBLES OF A NATURALIST. 



observations exclusively upon Rotifers which had been 

 taken from the dust that had collected round the gutters 

 on the tops of houses. These animals certainly occur in 

 such localities, but in much smaller quantities than in 

 the little tufts of moss which shoot up between the tiles 

 and slates on the house-tops, whilst very few are to be 

 met with among the moss that grows upon walls cemented 

 with lime. Our observations upon the Rotifers apply 

 equally to different species of Tardigrades, which are of 

 much more rare occurrence. They may be obtained by 

 moistening moss and then squeezing it as if it were 

 a sponge, when the water which flows from it will 

 dislodge both the sand and the animalcules which in- 

 habit it. 



Although the different species that I have indicated 

 may die. and be resuscitated several times in succession, 



exclusively to the natural sciences, which he was called upon to 

 teach at the University of Pavia, where he remained for the rest 

 of his life. He died in 1799. Spallanzani has left a large number 

 of memoirs and many works, the most important of which have 

 been translated into French by Sennebier, the librarian of Geneva. 

 Spallanzani may be regarded as one of the founders of experimental 

 physiology, and his researches on digestion and generation prove 

 that he possessed, in a most exceptional degree, a true genius for 

 experimentalising. Modern science has undoubtedly added to his 

 discoveries in reference to these difficult questions, but it has in no 

 respect changed the general results at which he arrived, and if he 

 was occasionally less happy in his microscopical observations, the 

 fault may be especially referred to the imperfect instruments then 

 in use. In his zeal for science he often made himself the subject of 

 his experiments, not unfrequently at the risk of his life. He 

 displayed a similar ardour in his scientific travels ; thus, when he 

 was anxious to confirm his observations on volcanoes for his work 

 on the Two Sicilies, he, although at the time more than sixty years 

 of age, approached the crater of Stromboli when it was in a state of 

 eruption, and ventured so near the burning lava of Vesuvius, that 

 he very nearly experienced the same fate as Pliny the Elder. 



