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Show 188 DROSERA ROTUNDIFOLIA. CHAP. YIII. and potassium,* which act so differently ; therefore we might expect that its action would. be intermeuiate. We see, also, that cmsium causes inflection, and rubidiu1n does not; and these two metals are allied. to sodium and potassium. Most of the earthy salts are inoperative. Two salts of calciu1n, four of magnesium, two of barium, and two of strontium, did not cause any inflection, and thus follow tho rule of the preponderant power of the base. Of three salts of aluminium, one did not act, a second showed a trace of action, and the third acted slowly and doubtfully, so that their effects are nearly alike. Of the salts and acids of ordinary metals, seventeen were tried, and only four, namely those of zinc, lead, manganese, and cobalt, failed to cause inflection. The salts of cadmium, tin, antimony, and iron, act slowly; and the three latter seem more or less poisonous. The salts of silver, mercury, golu, copper, nickel, and platinum, chromic and arsenious acids, cause great inflection with extreme quickness, and are deadly poisons. It is surprising, judging from animals, that lead and barium should not be poisonous. Most of the poisonous salts make the glands black, but chloride of platinum made them very pale. I shall have occasion, in the next chapter, to add a few rmnarks on the different effects of phosphate of ammonia on leaves previous! y immersed in various solutions. ACIDS. I will first give, as in the case of the salts, a list of the twenty-four acids which wore tried, divided into two series, according as they cause or do not cause * Miller's' Elements of Chemistry,' 3rd edit. pp. 337, 448. CHAP. VIII. THE EFF~CTS OF ACIDS. 1 9 inflectio:U. After describing the experiments, a few concluding remarks will be added. ACIDS, MCCH DIL"CTED, WIIICH CAUSE . INFLECTION. 1. Nitric, strong inflection; poisonous. 2. Hydrochloric, moderate and slow inflection; not poisonous. 3. Hyclriodic, strong inflection ; poisonous. 4. !odic, strong inflection; poisonous. 5. Sulphuric, strong inflection; somewhat poisonous. 6. Phosphoric, strong inflection ; poisonous. 7. Boracic, moderate and rather slow inflection; not poisonous. 8. Formic, very slight inflection ; not poisonous. 9. Acetic, strong and rapid inflection ; poisonous. 10. Propionic, strong but not very rapid. inflection ; poisonous. 11. Oleic, quick inflection; very poisonous. 12. Carbolic, very slow inflection ; poisonous. 13. l-actic, slow and moderate inflection ; poisonous. 14. Oxalic, moderately quick inflection ; very poisonous. 15. Malic, very slow but considerable inflection; not poisonous. 16. Benzoic, rapid inflection; very poisonous. 17. Succinic, moderately quick inflection; moderately poisonous. 18. Hippuric, rather slow inflection ; poisonous. 19. Hydrocyanic, rather rapid inflection; very poisonous. Acms, DlLU'l'ED TO TH:I!: SAME DEGREE, WHICH DO NOT CAUSE lN:FLECTION. 1. Gallic; not poisonous. 2. Tannic; not poisonous. 3. Tartaric ; not poisonous. 4. Citric; not poisonous. 5. Uric; (?) not poisonous. Nitric .Acid.-Four leaves were placed, each in thirty minims of on. e part by weight of the acid to 437 of water , so thnt each received l 6 of a grain, or 4·048 mg. This strength was chosen for this and most of the following experiments, as it is the same ,,.I |