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THE POPULAR SCIENCE MONTHLY. 



the first starts from ortho-nitro-benzoic 

 acid, which yields isatin after successive 

 treatment with phosphorus pentachloride, 

 silver cyanide, caustic potash, and nascent 

 hydrogen. The other, also by Baeyer, 

 starts from ortho-nitro-phenyl-acetic acid, 

 which, having been obtained synthetically 

 from toluol, is converted into the amido- 

 acid, then by the loss of water into a body 

 called oxindol, from which isatin, and there- 

 fore indigo, can be obtained. 



Tohaccoism. M. Thorens has published 

 some observations on angina pectoris caused 

 by tobaccoism. His attention was called 

 to the subject by the case of a patient who 

 had most of the symptoms of angina pec- 

 toris, but in whom no cause for the affec- 

 tion could be found except excessive smok- 

 ing. The patient smoked cigarettes, and 

 swallowed the smoke, thus making the 

 whole quantity of smoke pass through the 

 lungs. Evidently the opportunities given 

 for the absorption of smoke and nicotine in 

 this case were colossal in comparison with 

 those which would exist in a person smok- 

 ing ten times as much, but in an open place 

 and without swallowing the smoke. An- 

 other circumstance aggravating the affec- 

 tion was, that the patient smoked his cigar- 

 ettes directly, without the intervention of a 

 holder, so that the smoke reached his mouth 

 hot, without any chance having been given 

 for the condensation of any of the volatile 

 products. His mouth was, moreover, in con- 

 stant contact with the tobacco-leaves, so 

 that the liability of absorption by the buccal 

 membrane was greatly increased. Similar 

 affections arising from similar causes had 

 been noticed by Beau and M. Gelineau, a 

 naval surgeon, both of whom observed that 

 the trouble was mitigated when the use of 

 tobacco was moderated. The case surrcrcsts 

 a number of precautions to be observed by 

 persons who will smoke but desire to do 

 themselves as little harm as possible, among 

 which are never to swallow or inhale the 

 smoke ; to avoid smoking in an inclosed 

 place, or at least to have the room as large 

 and as well ventilated as possible ; and to 

 put as considerable a distance as is prac- 

 ticable between the light and the mouth, 

 always using for this purpose long-stemmed 

 pipes or cigar-holders. The driest tobacco 



and that which is weakest in nicotine, should 

 be preferred. M. Thorens exonerates to- 

 bacco from the charge of producing cancer, 

 although it is of course liable to irritate a 

 wound already made, or a surface that has 

 already been injured by heat. , . 



The Horse in America. It has been 

 generally believed that the horse was intro- 

 duced into America by the Spaniards. Pro- 

 fessor Marsh, on the other hand, has found 

 abundant remains of probable ancestors of 

 the horse in our "Western geological forma- 

 tions ; so that, if there were no horses be- 

 fore the Spaniards came, there must have 

 occurred a failure of the race. Mr. E. L. 

 Berthoud, of GoldeD, Colorado, believes that 

 he has evidence that the Spaniards found 

 horses in South America when they first 

 visited it. Among the maps which he has 

 recently received from Paris, in a collection 

 of the fifteenth and sixteenth centuries, is 

 one which Sebastian Cabot drew for the 

 Emperor Charles V, representing his ex- 

 plorations of the La Plata and Parana 

 Rivers, and containing symbols of the ani- 

 mals and plants that he found. Among 

 these symbols was that of the horse repre- 

 sented near the plains of the Gran Chaco, 

 where the immense herds of that animal 

 range to-day. He claims that this affords a 

 fair presumption of the native origin of the 

 race, for neither the Spaniards nor the Por- 

 tuguese had then been lorg enough in the 

 country (in 1527) for their horses to have 

 escaped from Peru to the head of the Para- 

 guay and Parana Pavers and to have in- 

 creased in numbers sufficiently to attract 

 attention. 



The Protective Organs of Plants. Dr. A. 



Tschirch has recently published some inter- 

 esting observations on the relations of the 

 anatomical structure of plants to climate 

 and location. In the first place, the adjust- 

 ment of the breathing-pores appears to be 

 adaptable to a variety of external condi- 

 tions in different plants of the same fam- 

 ily. In plants that grow in a moist at- 

 mosphere, the pores are exposed with but 

 slight protection ; while the means of pro- 

 tection appear to increase gradually as the 

 habitat becomes drier, and reach the high- 

 est point in desert plants. The closed cells 



