July 26, 1889.] 



SCIENCE. 



61 



equinum) belonging to the family of Strongylidce, and that in many, 

 perhaps in a majority of cases, the existence of such an aneurism 

 must be considered, if not the sole, at any rate the principal, cause 

 of colic. 



Although not much that is really new can be added to what was 

 said in the annual report of 1886, and although no important dis- 

 coveries have since been made, the simple fact that since that report 

 was published such an aneurism has been found in every one of the 

 sixteen horses that have been killed for anatomical purposes in the 

 Veterinary College, or Veterinary Department of the Ohio State 

 University, and that said aneurism was found not only in old horses, 

 but also in young horses and in mules, will more than corroborate 

 what was said two years ago, and be of interest to science, and of 

 practical value to the farmer and horse-owner. As to the occur- 

 rence of the aneurism in young horses. Dr. Detmers states, that, 

 among the sixteen horses and mules killed for anatomical purposes 

 since the publication of the fifth annual report, were two young 

 horses (one last year, and one this winter) which were each less 

 than two years old, consequently mere colts, and that both had big 

 aneurisms containing quite a large number of worms. 



As colic is one of the most frequent diseases of horses, which, 

 notwithstanding its frequent occurrence, is but little understood 

 even by the majority of veterinarians, and consequently a disease 

 which is seldom rationally treated, and perhaps oftener than any 

 other a subject of quackery of the grossest kind ; further, as it 

 causes every year great losses, partially due to its often dangerous 

 ■character, and partially to irrational treatment, — this brief treatise 

 ■on colic, showing the causal connection between the aneurism and 

 the morbid process, explaining its true causes, describing the symp- 

 toms, etc., giving a rational treatment, and pointing out the means 

 of prevention, will be appreciated by farmers and horse-owners. 



As to colic, it will, on the whole, be easier to ward off or to pre- 

 vent the exciting than the predisposing causes. A prevention of 

 the principal and most frequent exciting causes will be effected if 

 the horse is always regularly fed ; if the food is sound, wholesome, 

 and digestible ; if feeding a heavy meal immediately before and 

 immediately after severe exercise is avoided ; if no food that has a 

 tendency to ferment, or that is rich in alkalies, is given ; if the feed- 

 ing of new grain and of new hay that has not yet passed through 

 the so-called " sweating process " is avoided, or, where that cannot 

 be done, if such new hay and new grain are fed only in small quan- 

 tities, and then with a small pinch of salt added to each meal ; if 

 no icy food, or food covered with hoar-frost, is allowed to be eaten ; 

 if no ice-cold water is given to drink, or, when it cannot be avoided, 

 only in small quantities, and never when the horse is perspiring or 

 has an empty stomach ; and, finally, if meal or bran that may be 

 used as food is never given until it has been thoroughly moistened. 



The principal predisposing cause, according to Dr. Detmers, — 

 the aneurism in the anterior mesenteric artery, — can be warded 

 off by preventing the worm-brood of Sclerostomum eguinum from 

 entering the digestive canal of the horse ; but this, it seems, can 

 only be accomplished if the horse is never allowed to drink any 

 water but what is positively free from the worm-:brood. That this 

 will be difficult, will not need any explanation. 



This bulletin will be sent free to any resident of Ohio on applica- 

 tion to the Ohio Agricultural Experiment Station, Columbus, O. 



QUARTZ FIBRES. 



In almost all investigations which the physicist carries out in the 

 laboratory, he has to deal with, and to measure with accuracy, those 

 subtle and to our senses inappreciable forces to which the so-called 

 laws of nature give rise. Whether he is observing by an electrom- 

 ■eter the behavior of electricity at rest, or by a galvanometer the 

 action of electricity in motion ; whether in the tube of Crookes he 

 is investigating the power of radiant matter, or with the famous 

 experiment of Cavendish he is finding the mass of the earth, — in 

 these and in a host of other cases he is bound to measure with 

 certainty and accuracy forces so small that in no ordinary way 

 could their existence be detected ; while disturbing causes which 

 might seem to be of no particular consequence must be eliminated, 

 if his experiments are to have any value. It is not too much to 

 say that the very existence of the physicist depends upon the 



power which he possesses of producing at will and by artificial 

 means forces against which he balances those that he wishes to 

 measure. 



The weight of a single grain is not to our senses appreciable, 

 while the weight of a ton is sufficient to crush the life out of any 

 one in a moment. A ton is about 15,000,000 grains. It is quite 

 possible to measure with unfailing accuracy forces which bear the 

 same relation to the weight of a grain that a grain bears to a ton. 



To show how the torsion of wires or threads is made use of in 

 measuring forces, simply hang a straw horizontally by a piece of 

 wire. Rest on the straw a fragment of sheet-iron. A magnet so 

 weak that it cannot lift the iron is able to pull the straw round 

 through an angle so great that the existence of the feeble attraction 

 is plainly evident. 



Ordinary spun glass, a most beautiful material, is about one- 

 thousandth of an inch in diameter, and this would appear to be an 

 ideal torsion-thread. Owing to its fineness, its torsion would be 

 extremely small, and the more so because glass is more easily de- 

 formed than metals. Owing to its very great strength, it can carry 

 heavier loads than would be expected of it. It has every good 

 quality but one, and that is its imperfect elasticity. For instance : if 

 a mirror is hung by a piece of spun glass, and if you turn the mir- 

 ror twice to the right, and then turn it back again, a ray of light 

 reflected from the mirror does not come back to its old point of 

 rest, but oscillates about a point on one side, which, however, is 

 slowly changing, so that it is impossible to say what the point of 

 rest really is. Further, if the glass is twisted one way first, and 

 then the other way, the point of rest moves in a manner which 

 shows that it is not influenced by the last deflection alone : the 

 glass remembers what was done to it previously. For this reason 

 spun glass is quite unsuitable as a torsion-thread. It is impossible 

 to say what the twist is at any time, and therefore what is the force 

 developed. 



So great has the difficulty been in finding a fine torsion-thread, 

 that the attempt has been given up, and in all the most exact in- 

 struments silk has been used. The natural cocoon fibres consist 

 of two irregular lines gummed together, each about one two- 

 thousandth of an inch in diameter. These fibres must be sepa- 

 rated from one another and washed. Then each component will, 

 according to the experiment of Gray, carry nearly 60 grains before 

 breaking, and can be safely loaded with 15 grains. Silk is there- 

 fore very strong, carrying at the rate of from 10 to 20 tons to the 

 square inch. It is further valuable in that its torsion is far less 

 than that of a fibre of the same size of metal, or even of glass, if 

 such could be produced. The torsion of silk, though exceedingly 

 small, is quite sufficient to upset the working of any delicate in- 

 strument, because it is never constant. At one time the fibre 

 twists one way, and another time in another, and the evil effect can 

 only be mitigated by using large apparatus in which strong forces 

 are developed. Any attempt that may be made to increase the 

 delicacy of apparatus by reducing their dimensions is at once pre- 

 vented by the relatively great importance of the vagaries of the silk 

 suspension. 



The result, then, is this : the smallness, the length of period, and 

 therefore delicacy, of the instruments at the physicist's disposal, 

 have until lately been simply limited by the behavior of silk. A 

 more perfect suspension means still more perfect instruments, and 

 therefore advance in knowledge. 



As nothing that Mr. C. V. Boys, F.R.S., knew of could be obtained 

 that would be of use to him, he was driven to the necessity of try- 

 ing by experiment to find some new material. The result of these 

 experiments was the development of a process of almost ridiculous 

 simplicity. 



The apparatus consists of a small cross-bow, and an arrow made 

 of straw with a needle-point. To the tail of the arrow is attached 

 a fine rod of quartz which has been melted and drawn out in the 

 oxyhydrogen jet. The operator holds a piece of the same material 

 in his hand, and, after melting their ends and joining them to- 

 gether, — an operation which produces a beautiful and dazzling 

 light, — all he has to do is to liberate the string of the bow by 

 pulling the trigger with one foot ; and then, if all is well, a fibre 

 will be drawn by the arrow, the existence of which can be made 

 evident by fastening to it a piece of stamp-paper. 



