728 



PHYSIOLOGY. 



notwithstanding several years' successful cultiva- 

 tion, does not consider the experiment complete, 

 and will continue the investigation. It could 

 easily be prosecuted by every one with rasp- 

 berry plants. 



Australian sheep are said to thrive wonder- 

 fully upon the " scrubby " plants of the Atriplex 

 family, which grow abundantly in some of the 

 pastoral districts of the country, and to secure 

 an immunity from disease that is unknown in 

 the richest grass districts. Analyses of speci- 

 mens of two of the species by R. W. E. Macivor 

 show that they contain more than twice (26'61 to 

 27'60 per cent.) of the average quantity of ash 

 found in any other known plants. Their high 

 value as fodder is due to the proportion of car- 

 bonaceous and albuminous nutrients they con- 

 tain, and also to the chlorides and potash, which 

 aid digestion and contribute to the production 

 of " surut." 



Experiments have been made by M. De Can- 

 dolle with various hardy seeds to determine the 

 effect of the temperature of congelation upon 

 germination. They go to show that while seeds 

 can be kept in damp air and darkness at the 

 temperature of the freezing point without im- 

 pairing their vitality, germination will not take 

 place at that temperature. 



Poisons. Experiments by M. Greenwood on 

 the action of nicotine upon certain invertebrates 

 show that the toxic effect of this agent on any 

 organism is determined mainly by the degree of 

 development of the nervous systems. In the 

 simplest animals, as amoeba, etc., it can not be 

 regarded as exciting or paralyzing; it is rather 

 inimical to continued healthy life. As soon as 

 any structural complexity is reached the action 

 of nicotine is discriminating, and discriminating 

 in such a fashion that the nervous actions, which 

 are the expression of automatism which imply 

 co-ordination of impulse are stopped first. In- 

 the higher invertebrates, the paralyzing action 

 of nicotine is preceded by a phase of stimulation. 

 As this positively exciting action becomes no- 

 ticeable, nicotine becomes more and more a me- 

 dium in which life is impossible. When very 

 simple animals die under the action of nicotine, 

 death is associated with injury of their substance, 

 so that it tends to disintegrate. The definite 

 poisoning that occurs in higher types has some- 

 times as one of its after-effects a lingering tro- 

 phic disturbance. While nicotine acts on any 

 organism according as the nervous system is or 

 is not developed, animals which have enough in 

 common to stand near each other in classifica- 

 tion may yet react differently, each according to 

 what may be called its own balance of organiza- 

 tion. 



The experiments of Dr. T. J. Mays 'on the dif- 

 ferential action of brucine and strychnine upon 

 the frog, while they demonstrate that the two 

 alkalies have a few points of action in common, 

 also show that they possess so many dissimilar 

 points as to justify the belief that their differ- 

 ence is one of kind as well as of degree. Their 

 agreement of action consists in causing death by 

 arresting respiration, and in tending to produce 

 convulsions. The points of. difference are : 

 Brucine primarily affects the posterior, while 

 strychnine first affects the anterior extremities 

 of the frog; convulsions appear very early in 



strychnine, and if at all very late in brucine 

 poisoning; convulsions invariably develop be- 

 fore death occurs in strychnine poisoning, while 

 death very frequently occurs from pure brucine 

 poisoning without a trace of spasm ; brucine 

 diminishes sensibility when locally applied, while 

 strychnine does not ; the local anaesthetic effect 

 of brucine appears to bear a direct relationship 

 to its degree of freedom from strychnine. 



The results of an investigation of the method 

 of operation of chloroform are given in the re- 

 port of a commission of physicians who were 

 appointed by the Nizam of Hyderabad to take 

 the subject in hand. The commission availed 

 itself, in forming its conclusions, of the evidence 

 afforded by nearly 600 experiments, 157 of which 

 were made with, and 480 without recording ap- 

 paratus. The experiments of the latter class 

 were directed, first, to the general action of 

 chloroform given in various ways, in various di- 

 lutions, and in different conditions of the ani- 

 mal ; and, second, to the limits within which 

 artificial respiration may restore life, and the 

 effect of morphine, strychnine, atropine, and 

 other drugs in modifying the action of the an- 

 aesthetic and the reviving power of artificial 

 respiration. Two views regarding chloroform 

 are commonly held one that it may kill by 

 paralyzing the heart directly ; the other that it 

 really kills by paralyzing respiration, and only 

 stops the heart indirectly through the asphyxia 

 which quickly follows stoppage of the respira- 

 tions. The result of the labors of the commis- 

 sion appears to show that there is some truth in 

 both views, but that when chloroform is given in 

 the ordinary way by inhalation, it is the respira- 

 tion that is stopped first. When chloroform 

 vapor is blown down the trachea, the heart may 

 be stopped by it, but when the vapor is drawn 

 into the lungs in the usual way by the move- 

 ments of the chest, this is not the case, for, the 

 respiratory movements being arrested first, their 

 stoppage prevents any more chloroform vapor 

 from being taken into the lungs. Embarrass- 

 ment of respiration constitutes the first sign of 

 danger, and should be attended to at once. The 

 breathing should not be allowed to stop, but if 

 it should do so by any accident, life may still be 

 preserved by the use of artificial respiration. 

 Should the interval of asphyxia between the 

 stoppage of natural breathing and the com- 

 mencement of artificial respiration be too long, 

 the heart may fail to such an extent that artifi- 

 cial respiration is in vain ; and if the adminis- 

 trator waits for a falling pulse to warn him of 

 danger, the warning may come too late. Some 

 previous experiments by a committee of the 

 British Association seemed to show that chloro- 

 form not only lowers the blood pressure and 

 paralyzes the heart, but does so sometimes in an 

 unexpected and capricious manner. The com- 

 mission repeated these experiments, and found a 

 similar fall of blood pressure and lowering of 

 the pulse, but attributed them to asphyxia rather 

 than to chloroform. The work of the commis- 

 sion thus points to the conclusion that deaths 

 from chloroform in man are due to asphyxia; 

 and the commission considers that by careful 

 attention to the respiration all deaths may and 

 should be prevented. 

 ' In his experiments on the preventive inocula- 



