120 



CHEMISTKY. 



grains for the whole body. A striking feature 

 of the results was the irregular distribution of 

 the arsenic in the muscular tissue,%which va- 

 ried from nothing in the bone up to a quarter 

 of a grain per pound in the muscle of the 

 back, whereas, in cases of chronic poisoning, or 

 where arsenic is habitually used, the distribu- 

 tion is generally quite regular. The irregu- 

 larity is regarded as indicative of the arsenic 

 having been taken but a short time before 

 death, particularly as the larger proportions of 

 poison in the muscular tissue were observed in 

 the parts nearer to the great vessels and or- 

 gans. It is usual in cases of chronic poisoning 

 to find a considerable proportion of the poison 

 in the kidneys. In the present case only a 

 small proportion was found there, while the 

 tongue and throat contained nearly three times 

 as much, or nearly as much as was contained 

 in the entire left arm. It has been asserted 

 that the presence or absence of arsenic in the 

 brain is an index as to whether the poison was 

 introduced into the body before or after death. 

 The finding of arsenic in the brain may be re- 

 garded as proof that its introduction was not 

 post mortem, but its absence can not be held to 

 prove the contrary. The amount of arsenic 

 found in the brain in the present case can be 

 regarded only as indicating that it was taken 

 in a form readily soluble and diffusible. 



Passive and Active Oxygen. Moritz Traube 

 has published a discussion of the circumstances 

 under which oxygen experiences the remark- 

 able change of passing from the ordinary pas- 

 sive to the active condition. Considering the 

 formation of hydrogen dioxide under the influ- 

 ence of the slow oxidation of metals in the 

 presence of water and air, he concludes, from 

 such experiments as he has made, that the 

 process is not one of the oxidation of water, 

 but a reduction process, in which the dioxide 

 is probably formed by the addition of hydrogen 

 directly to oxygen. Oxygen, at the ordinary 

 temperature, is characterized by great passivi- 

 ty, but in the animal body it becomes active, 

 and has the power of effecting oxidations at 

 temperatures below 40 C. (104 F.), which it 

 can otherwise effect only at a red heat. Re- 

 garded from this stand-point, the adult animal, 

 which neither loses nor gains in weight, plays 

 the part of a catalytic body, which, without 

 suffering material change in composition, causes 

 at low temperatures, by means of the oxygen of 

 the air, the almost complete combustion of 

 enormous quantities of food. Plants also, or, 

 in general, all organisms down to and includ- 

 ing bacteria and fungi, possess the same prop- 

 erty, though to a much less extent; and there 

 does not exist an organism which is indifferent 

 toward oxygen. Herr Traube further assumes 

 that he has pointed out, " with conclusive rea- 

 sons," that the real hearth of the respiratory 

 processes in animals is not the blood, but the 

 tissues of the body, above all, the muscles ; that 

 the oxygen taken up in the lungs is set free in 

 the capillaries of the body, and enters as dis- 



solved gas into the tissues of the individual or- 

 gans ; and that in this way each individual 

 organ breathes independently at the expense 

 of the free oxygen. Thus, not only do organ- 

 isms as a whole have the power to make oxy- 

 gen active, but each of their organs, indeed 

 each individual cell; or, rather, they contain 

 substances which have the power. Hence the 

 problem of active oxygen is in the highest de- 

 gree important, as well for physiology as for 

 chemistry. 



Constancy of the Amount of Carbonic Acid in the 

 Air. Very careful determinations of the propor- 

 tion of carbonic acid in the atmosphere at dif- 

 ferent places have been made by M. J. Reiset, 

 with a particular view to answering the ques- 

 tions : For a given place is there more or less 

 carbonic acid in the air on a clear day than on 

 a cloudy day ? Is there a difference in the pro- 

 portion between day and night, or between win- 

 ter and rammer? Is there more or less car- 

 bonic acid at the bottom of a mountain than at 

 the top? Is there more or less in the air near 

 the sea than in the inland country ? etc. His 

 tests were made by the precipitation of car- 

 bonate of baryta by passing a known volume 

 of air through a solution of baryta. His investi- 

 gations have led to the conclusions that the 

 maxima in the proportion of carbonic acid 

 always correspond to cloudy, foggy, or misty 

 weather; that air collected in the night con- 

 tains more carbonic acid than that collected 

 during the day, and that the minima of the 

 acid correspond to days of fine weather, with 

 bright sunlight and absence of clouds. Investi- 

 gations to ascertain the effect of vegetation on 

 the proportion were made difficult by the 

 rapid diffusion of the gas in the air, and the 

 variations were hardly appreciable. They in- 

 dicated, however, a diminution of the propor- 

 tion over growing fields. The presence of a 

 flock of three hundred sheep near the ap- 

 paratus on a certain day of fine weather, 

 caused a notable increase in the proportion 

 of the acid. A number of analyses were made 

 near the Pare Monceau in Paris. During the 

 month of May, when fires began to be extin- 

 guished, the mean was found to be 30-57 per 

 100,000 of air. The maximum, 35-16, was 

 obtained on the 27th of January, 1879, dur- 

 ing the period of most active combustion ; the 

 minimum, 29'13, was obtained May 31, 1875. 

 The normal variations in proportion are gen- 

 erally between 28 and 30 per 100,000 of air, 

 and are more sudden and more numerous dur- 

 ing the summer. Determinations made by 

 MM. Muntz and E. Aubin, in the city of Paris 

 and in the open country near Vincennes, 

 gave results substantially agreeing with those 

 of M. Reiset, and indicate that carbonic acid 

 is uniformly distributed throughout the lower 

 strata of the atmosphere, while variations in 

 the proportion occur only between very nar- 

 row limits, and are due to local influences. 

 MM. Muntz and Aubin also applied their analy- 

 ses to the upper strata, fixing their station 



