P OP TJLAR MIS CELL ANY. 



761 



talline concentric layers, and attain to eigh- 

 teen or twenty inches in diameter. This, 

 he thinks, is the greatest size they can at- 

 tain. When so large as this, they press 

 out the sides of the intestine, producing in- 

 flammation and violent pain, which causes 

 the animal to roll about in agony, and, soon- 

 er or later, kills him. They consist mostly 

 of phosphate of ammonia and magnesia, 

 and the amount of organic matter is not 

 great. This salt the author refers to the 

 grain fed to the animals, and he raises the 

 question whether grain is not for the horse 

 a highly-artificial food. He is of the opin- 

 ion that repeated doses of very dilute hy- 

 drochloric acid, say two to five per cent., in 

 water or spirit, if it can be made to reach 

 them, would quickly destroy the largest of 

 these calculi. The lime in the water drunk 

 by horses has nothing to do with the pro- 

 duction of these concretions. It originates 

 in the food, and is, in a large measure, due 

 to a want of salt in the grain. Hence, 

 working-horses that are highly fed should 

 have lumps of salt to lick, and have salt in 

 their food, and plenty of water to drink. 

 The ventilation and drainage of stables is 

 another important consideration. Many 

 valuable beasts, after a hard day's work, 

 pass the night in an atmosphere loaded 

 with fumes of ammonia. 



Abnormal Fruits. Some abnormal fruits 

 of the pear-tree, in appearance like very 

 large acorns, having been exhibited at a 

 meeting of the Academy of Natural Sci- 

 ences of Philadelphia, Mr. Meehan took 

 occasion to explain that a fruit is a modifi- 

 cation of both leaves and branch. When 

 a bud, he said, is being formed in the 

 apple, pear, or similar trees, it may finally 

 be either a flower-bud or a bud producing 

 a new branch. Varying phases of nutrition 

 decide this question. Exactly the nature 

 of this variation we do not know ; but we 

 do know that the growth-force in the bud 

 is arrested by some law of nutrition, and, 

 instead of an elongated branch, what would 

 be its series of spirals are drawn together 

 closely, and the whole modified and made 

 to form a flower. Thus, in the pear, it 

 takes five buds to form one full cycle on a 

 branch. When growth is arrested to form 

 a flower, this first cycle is transformed into 



a five-lobed calyx, and generally this be- 

 comes much enlarged and fleshy, and cov- 

 ers all the other cycles of buds, which go 

 to make up the inner layer of flesh termi- 

 nating in the petals, carpels, or core, and 

 so on. In the case under consideration the 

 arresting force was imperfect. It had suc- 

 ceeded in forming the outer or calycine 

 verticillate series of buds into a fleshy mat- 

 ter, giving what here might be called the 

 cup of the "acorn ;" but then the acceler- 

 ating or branch-producing force gained a 

 temporary advantage, and pushed on, form- 

 ing the acorn-like centre, but only to be 

 soon again arrested. This abnormal pear 

 was, indeed, nothing more than an effort of 

 the tree to produce a branch after a fruit 

 had been decided on a struggle which was 

 finally decided in favor of the fruit. 



Explanation of the Ball-Paradox. Reu- 



leaux offers the following explanation of the 

 curious phenomenon of a ball being sup 

 ported in air by a strong air-current di- 

 rected obliquely upon it at an angle of 35 

 to 40 from the vertical : The pretty thin 

 air-current, on reaching the ball, is deflect- 

 ed on all sides, and therefore more or less 

 rarefied in its interior. Accordingly, the 

 atmosphere presses the ball in the direction 

 of greatest rarefaction, or the mean force 

 of the rarefactions, toward the orifice. The 

 weight of the ball acts vertically downward. 

 Equilibrium occurs between the obliquely 

 acting force of the current and the two 

 forces just named, when the mean force of 

 the latter is parallel to the action of the 

 current. This can only take place when 

 the ball ha its centre under the axis of the 

 current. There are then two forces which 

 put the ball in rotation. If the finger or a 

 rod be brought to the place of supposed 

 minimum pressure on the ball, the latter is 

 forthwith driven off (the vacuum being de- 

 stroyed), or falls down. 



Successful Case of Transfusion of Blood. 



A case of successful transfusion of blood 

 is recorded in the Lancet. The patient, a 

 clerk, twenty years of age, was completely 

 demented, hypersemic, anaesthetic, and cata- 

 leptic ; refused all food ; dribbled constant- 

 ly. The pulse was very feeble, rate *70, res- 

 piration 24. His state was one of profound 



