106 



CHEMISTRY. 



both medical and surgical, and it is his opin- 

 ion that 



For internal and external use in domestic animals, 

 as n antiseptic and destroyer of living contagia, it 

 is destined to occupy as honorable a position in vet- 

 erinary practice as it does in human medicine. 



Kolbe has experimented on his own person, 

 to determine whether or not salicylic acid is 

 injurious to the animal economy. For several 

 days in succession he took daily, in four parts, 

 one-half gramme (solution in water 1 : 1,000), 

 without the slightest bad effect. After an in- 

 terval of eight days, he for five successive days 

 took double the former dose, and for two suc- 

 cessive days he took one and a half gramme. 

 In the mean time his digestion was entirely 

 normal ; there was no feeling of oppression in 

 the stomach, nor did he experience any incon- 

 venience whatever. Other physicians who, at 

 his request, made the same experiments, con- 

 firm these results. 



Some experiments have been made by Knop 

 to ascertain the action of salicylic acid on vege- 

 tation. The following account, which is taken 

 from the American Journal of Science and Arts, 

 proves that it exerts a marked influence on the 

 vegetative activity of cells, whether these be 

 the chlorophyll cells of the higher or the non- 

 chlorophyll cells of the lower orders of plants, 

 provided only the acid remain free in the liq- 

 uid. l ' Two vigorous maize-plants, four or five 

 decimetres high, grown in his well-known so- 

 lution and well rooted, were immersed in 500 

 c.o. of this solution, to which had been added 

 100 c.c. of a solution of salicylic acid contain- 

 ing 0.4 per cent, of the acid. A third, fourth, 

 and fifth plant was similarly treated, using tar- 

 taric, citric, and lactic acids respectively, in 

 place of salycylic. In the salicylic solution, 

 the roots were killed. The new roots put out 

 during the duration of the experiment became 

 dark upon their ends, and under the micro- 

 scope their cells were seen to be markedly af- 

 fected, the protoplasm separating from the 

 cell-walls. A second crop of roots fared simi- 

 larly ; but the third was more successful, and 

 the plant continued to live in the solution for 

 a long time. No mould, however, formed on 

 the surface of the liquid even after three 

 weeks. The other acid solutions killed the 

 maize-plants in three weeks, but the surfaces 

 were covered with a thick layer of mould. 

 Neither maize nor buckwheat grains germi- 

 nate after soaking in water to which an equal 

 volume of a saturated solution of salicylic 

 acid has been added, not even by planting in 

 earth. Fifteen grains of corn were soaked in 

 water containing TT J Tnr of salicylic acid, and 

 then placed in a germinating fluid consisting 

 of 50 c.c. gypsum solution, 50 c.c. solution 

 salycilic acid of 0.1 per cent., in a litre of wa- 

 ter; 14 failed to germinate. The same fact 

 appeared with buckwheat, wheat, rye, and 

 oats. A similar depression of vegetative ac- 

 tivity was observed in the case of mould ; the 

 difficulty of germinating seeds in solutions in 



June and July, owing to the rapid production 

 of mould, being entirely obviated by the use 

 of a highly dilute solution of salicylic acid." 



New Process for purifying Illuminating 

 Gas. An improved process for freeing illu- 

 minating gas from ammoniacal impurities, and 

 at the same time preserving the ammonia from 

 waste, has lately been invented and patented 

 by Prof. Benjamin Silliman, of New Haven, 

 Conn. According to the specification pub- 

 lished in the American Chemist for 'January, 

 1875, the process " consists in the use of cer- 

 tain acid salts placed in the path of the gas 

 for the purpose of removing the ammonia and 

 other impurities." It is well known that the 

 complete removal of ammoniacal compounds 

 has hitherto been attended with serious diffi- 

 culty, as it required the use of water, and this 

 impaired the illuminating power of the gas by 

 washing out some of its more valuable con- 

 stituents. In the new process water is not 

 employed, the ammonia is entirely removed, 

 and the illuminating power of the gas thereby 

 much increased. The separation is said to be 

 so perfect, that not a trace of ammonia can be 

 detected with either turmeric or litmus paper, 

 after the gas has passed the purifiers. 



The material employed as the purifying agent 

 in this method is the salt-cake of acid and al- 

 kali works. This is broken up into a coarse 

 powder and placed in layers of convenient 

 thickness in boxes or trays similar to those 

 used in "dry-lime purification" or " oxide- of- 

 iron purification." Owing to the greater firm- 

 ness and porosity of the salt-cake it may be em- 

 ployed in thicker layers than are used when 

 lime is the purifying material. 



The gas as it comes from the hydraulic main 

 is made to pass through these layers of salt- 

 cake, which immediately and completely re- 

 move all ammoniacal compounds; holding them 

 in chemical combination in a dry state, and 

 thereby acquiring increased value in proportion 

 to the amount of ammonia absorbed and com- 

 bined. The power of the salt-cake to extract 

 the ammonia from the gas depends upon the 

 degree of acidity, which may be readily de- 

 termined beforehand. Salt-cake from the hy- 

 drochloric-acid process in the United States 

 usually contains about twenty-five per cent, 

 of pure hydrochloric acid, together with some 

 sulphuric acid. Nitric acid salt-cake contains 

 here from twelve to fifteen per cent, of nitric 

 acid ; but if desired the chemical manufacturer 

 may readily prepare the salt-cake of any de- 

 gree of acidity considered requisite for the 

 process. 



The product resulting from the union of the 

 ammonia with the salt-cake is much more val- 

 uable than the raw material employed, as the 

 ammonia may be readily separated, when it 

 finds a ready market, while the soda-salt is 

 left in a state fit for the soda process. 



Briefly summed up, the advantages claimed 

 are, a great reduction in the amount of water 

 required in gas-manufacture, increased ill ami- 



