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THE POPULAR SCIENCE MONTHLY. 



long ! It was certainly gigantic enough to 

 entirely disprove the theory, generally ac- 

 cepted, that the elephant is as large as any 

 animal can be that moves upon the land, 

 for the bulk of this reptile must have been 

 at least three times that of any known 

 Proboscidian. 



Among the other Dinosaurs described in 

 this paper is Morosaurus impar, another 

 herbivore belonging to the same family, 

 and about twenty-five feet in length, and 

 Creosaurus atrox, its carnivorous enemy, 

 nearly as large, each representing a new 

 genus. Two small species, belonging to the 

 new genus Laosaurus, are also described. 

 The large herbivorous Dinosaurs, from the 

 American Jurassic, represent, according to 

 Prof. Marsh, a well-marked family, the At- 

 lantosauridce, which have but three or four 

 vertebrae in the sacrum, five well-developed 

 digits in each foot, and the hind-feet ungu- 

 late and plantigrade characters not before 

 found in Dinosaurs. 



Trees and Health. Certain observations 

 made by a correspondent of the Chemical 

 Neivs are deserving of the attention of sani- 

 tarians. According to him, the cantonment 

 of Goruckpoor, in Northwest India, though 

 situated near the forest and in the neigh- 

 borhood of a large swamp, was thirty years 

 ago considered a healthy station. A large 

 grove of mango-trees existed between the 

 swamp and the station. For some reason 

 this grove was cut down, and the station be- 

 came unhealthy. Again, the civil station of 

 Futtehpoor is situated between Allahabad 

 and Cawnpoor, in an arid plain, but near a 

 pretty extensive marsh. This place was con- 

 sidered extremely unhealthy, until the ma- 

 gistrate planted between the station and the 

 swamp a belt of quick-growning babool-trees. 

 As the trees grew, the place became much 

 less unhealthy. In these two cases the trees 

 appear to have acted as a screen or filter, 

 protecting the population from the effects 

 of the malaria generated in the swamps. It 

 may be added that it would be difficult to 

 find trees more dissimilar in foliage than 

 the mango and the babool. " Is it not prob- 

 able," asks the author, " that where benefi- 

 cial effects have followed the planting of the 

 eucalyptus, the same may be due as much 

 to the screen which the plantation has inter- 



posed, as to any peculiar action of, or ex- 

 halation from, the leaves or stem of the 

 tree ? " Referring to the changes produced, 

 as regards salubrity, at the Trappist monas- 

 tery of Tre Fontane, near Rome, which 

 changes have been ascribed to the peculiar 

 virtues of the eucalyptus, the author calls 

 attention to the fact that the deep ploughing 

 of the soil and the removal of seven hun- 

 dred cart-loads of human bones from the 

 precincts of the monastery may perhaps be 

 credited with some share in producing the 

 change. So, too, the eucalyptus-trees may 

 have served, in this case also, as a screen. 



Carnivorous Plants. Mr. Francis Dar- 

 win, in a paper entitled " The Nutrition of 

 Drosera rotund if olia" describes a series of 

 experiments made by himself to determine 

 whether or not insectivorous plants profit by 

 their carnivorous habits. With this object 

 two hundred plants of Drosera rotundifolia 

 were transplanted (June 12, 1877) and culti- 

 vated in six soup-plates filled with moss dur- 

 ing the rest of the summer. The area of each 

 plate was equally divided by a low wooden 

 partition, one side being destined for the 

 plants to be fed with meat, the other for 

 those to be starved. Access of insects was 

 prevented by inclosing the plants in a gauze 

 case. The method of feeding consisted in 

 supplying each leaf (on the fed sides of the 

 six plates) with one or two small bits of 

 roast-meat, each weighing about one-fiftieth 

 of a grain, every few days. On July 17th 

 it was evident that the leaves on the " fed " 

 side were of a distinctly brighter green, 

 showing that the increased supply of nitro- 

 gen had allowed a more active formation of 

 chlorophyll-grains to take place. From this 

 time forward the " fed " sides of the plates 

 were clearly distinguishable by their thriving 

 appearance and their numerous tall and stout 

 flower-stems. On August 7th the ratio be- 

 tween the number of " starved " and " fed " 

 flower-stalks was 100: 149.1. And on com- 

 paring the number of stems actually in flow- 

 er, it was clear that the starved plants were 

 losing the power of throwing up new flower- 

 stems at an earlier date than their rivals. 

 In the middle of August the leaves were 

 counted in three plates, and were found to 

 be one hundred and eighty-seven on the 

 starved and two hundred and fifty-six on 



