August 4, 1893. J 



SCIENCE. 



59 



What the outcome of this innovation will be, or where it will 

 end, is at present impossible to say. The field is so broad and 

 the inclination to experiment so great that, in all probability, some 

 little time will elapse before the returns will all be in. Whether 

 these extracts exert any specific action, or whether the results 

 thus obtained have been through " suggestion " and auto-sugges- 

 tion, is likewise hard to explain, the writer is inclined to the 

 latter view, that " sugo;estion " has been the "specific" agent. 



NOTES ON ARSENIC. 



BY JAS. LEWIS HOWE, POLYTECHNIC SOCIETY, LOUISVILLE, KY. 



Notwithstanding the well recognized danger of arsenical greens 

 as coloring matei-ials, their use is still far too common, especially 

 in green enameled papers for covering boxes and for more repre- 

 hensible purposes. I cite two cases in point. 



1. Some time since my attention was called to some so-called 

 " Kiss Candies " for sale in a little variety shop, largely patronized 

 by the children of a neighboring public school. These candies 

 were squares of caramel, etc., each wrapped up with a verse of 

 jDoetry (?) in a piece of colored paper, together with other candies 

 not wrapped. Some of these papers were colored with anilin 

 dyes, but a very considerable number were green enameled 

 papers. An examination of several of these latter revealed the 

 following : — 



Paper I. Bright-green surface, 50 square centimetres, arsenic 

 found (estimated as arsenious oxid), 0.0285 of a gram. 



Paper II. Light-green surface, 50 square centimetres, arsenic 

 found, 0.0062 of a gram. 



Paper III. Dark-green surface, 50 square centimetres, arsenic 

 found, 0093 of a gram. 



Paper IV. Bluish-green surface, 47 square centimetres, arsenic 

 found, 0.0309 of a gram. 



In the latter cases the enameled surfaces appeared much abraded, 

 doubtless by contact with the other candies. 



It is needless to say that here was not only a grave danger of 

 the surfaces of the candies containing considerable arsenic, but 

 the well-known habit of young children of putting everything 

 bright colored in the mouth, might have easily resulted in taking 

 a toxic dose. 



3. Very recently there has appeared in the market a natural 

 leaf twist chewing tobacco, wrapped around with a strip of green 

 enameled paper three-fourths of an inch wide and about six inches 

 long, fastened to the tobacco by a tack. The surface of this paper 

 is an arsenic green. An examination was made of the twist by 

 cutting ofl: the exterior and using Reinsche's test. Distinct traces 

 of arsenic were found. The quantity from a single twist was far 

 too small to be dangerous, but it is needless to say that the prac- 

 tice of using arsenic paper under such circumstances should be 

 condemned, and the manufacturers of the twist were cautioned 

 on the point. The arsenic found in the tobacco doubtless came, 

 by abrasion, from the paper wrapped around it, but there is an- 

 other possibility. It is more or less widely known that Paris- 

 green is used by tobacco-growers against the tobacco worm. 

 While in general, when properly used, probably no danger is to 

 he apprehended, it has occurred in my knowledge that tobacco 

 has been sprayed very shortly before gathering. This would seem 

 to be dangerous, and investigations upon this point are being now 

 carried out. 



As I'egards the detection of arsenic in medico-legal cases, atten 

 tion has been called by Dr. Bernard Dyer in the Proceedings of 

 the Chemical Society ' to the fact that in certain cases, at least, a 

 lai'ge proportion of the arsenic is precipitated upon the zinc in 

 Marsh's test. The following is an observation in point. Arsenic 

 was recovered in a certain case by Reinsche's test on six pieces of 

 copper foil, each 20 square centimetres surface. Three of the 

 pieces were divided, and from each the arsenic was sublimed in 

 well-defined crystals, which could be identified without difficulty. 

 From the other three pieces all the arsenic was sublimed, dissolved, 

 and submitted to Marsh's test. Only the very slightest trace of a 

 mirror was found, not enough to identify it as arsenic in a doubt- 

 ful case. In this case, as in that of Dr. Dyer, cast zinc was used. 

 ' Proc. Chem. Soc, 1893, p. 120. 



Another recent case illustrates the necessity of the physicians 

 who perform the autopsy preserving other organs than the stom- 

 ach. G. had given her husband coffee from a pot in which she 

 had emptied probably a whole box of Rough on Rats. He drank 

 two cups, containing probably in the neighborhood of 7 grams. 

 The coffee left, which I afterwards examined, was practically a 

 saturated solution of arsenious oxid. Death ensued in four hours. 

 The stomach was brought me, and was found to be empty, and 

 much inflamed. Using the whole stomach, but a very small 

 quantity of arsenic was found, evidently only what the walls of 

 the stomach as a tissue could absorb, and far from enough to have 

 produced death. The corroborative testimony was, however, 

 sufficient to secure the woman's conviction. 



Brodie's statement that when arsenic is taken in solution no 

 trace of it will be found in the stomach is too broad, but it is 

 imperative that in such cases other organs, notably the liver (as 

 well as spleen and kidneys), should be preserved for analysis. 



In my own experience, Reinsche's lest, when carefully carried 

 out, is far more satisfaotory and no less certain in testing for the 

 presence of arsenic than Marsh's. It can be readily learned by 

 medical students and used practically by the physician, which is 

 not true of Marsh's test. In order to secure well-defined arsenic 

 crystals in Reinsche's test with a minimum of arsenic, I have 

 found it desirable to use electrolytic foil, to roll the strip very 

 closely, and to sublime in a tube of the smallest possible diameter. 



A NEW IDEA IN MICROSCOPE CONSTRUCTION. 



BY C. W. WOODWORTH, UNrVBBSITY OP CALIFOENIA, BBKKELET, CAL. 



Everyone who has worked with the microscope, especially in 

 studying rather large objects with medium and low powers, has 

 felt the need of a better means of orientation than those at present 

 available. 



Stage forceps admit of complete rotation in one direction and 

 some degree of motion at right-angles to this by raising or lower- 

 ing the object and readjusting the focus. Ordinarily, any change 

 in the direction of the object requires this readjustment of the 

 focus, and generally the part to be studied is out of the field and 

 must be found as well. 



The ideal condition would be to rotate the object at the exact 

 focal point of the microscope, and one can readily see that this 

 could be attained if the object was supported by an apparatus re- 

 volving upon two axes at right-angles to each other, which inter- 

 sect at the focal point, provided neither of these remains fixidly 

 coincident with the optical axis. 



There are many ways by which this condition might be attained, 

 but perhaps as simple a modiScation of an existing stand as could 

 be made with this object in view is a stand I have recently had 

 the Bausch & Lomb Optical Company make for the Entomological 

 Department of the University of California. 



The instrument is a " iModel " stand with an ordinary revolving 

 mechanical stage. This is supported on a rotating bar, resembling 

 the usual sub stage bar, and provided with a rack and pinion ad- 

 justment. 



The stage is centred in the usual way, which brings the axis 

 of revolution coincident with the optical axis. The stage bar 

 swings upon a core which is adjustable laterally, so it becomes 

 possible to make the axis of its rotation intersect the optical axis. 



These adjustments being made, the instrument fulfils the con- 

 ditions specified above whenever the focal point is brought to the 

 axis of rotation of the stage bar. Consequently, in using the in- 

 strument the tube is brought to a certain position and the focusing 

 of the object accomplished by means of the rack and pinion of 

 the stage bar. The correct position of the tube is determined by 

 trial for each objective, and marks made on the tube to indicate 

 this position. 



Different objectives, as those who have used revolving stages 

 must have noticed, have somewhat different optical axes, and 

 there is enough variation with the medium powers to make a 

 centreing nose-piece essential. 



While it is mechanically impossible to make all these adjust- 

 ments perfectly correct, still I find that even with medium powers 

 the object remains in the field during orientation, and that the 



