October 4, 1U94] 



NA TURE 



:)o' 



Brunton, for they find that if the presence of amyl nitrite 

 is confined to the vessels of the brain alone, a fall of 

 pressure does not take place, but it does occur if blood 

 containing the nitrite circulates in the peripheral vessels 

 of the body, even though the access of any nitrite to the 

 brain is prevented. They likewise find that nitrites arc 

 capable of influencing vessels in the area supplied by 

 the splanchnic nerves after section of these nerves — 

 another proof that the action of the nitrites is peripheral. 



The part which the group NO^, plays in its fatty 

 compounds they have sought to determine by ascertain- 

 ing quantitatively the comparative amount of influence 

 which each nitrite exerts on blood pressure, pulse fre- 

 quency, and respiration, when introduced into the circula- 

 tion of anxsthesised cats, by inhalation or by injection 

 into the arterial or venous system, and also by ascertain- 

 ing the comparative effect of paraffinic nitrites on the 

 pulse frequency in man. 



The quantitative method is doubtless open to some falla- 

 cies, but from the extreme care which has manifestly been 

 taken in conducting the experiments, and the laborious 

 manner in which they have been repeated, it seems 

 certain that the results are in the main reliable. With 

 regard to the influence of the nitrites in accelerating the 

 beat of the heart, it is shown that physiological activity 

 increases with molecular weight ; amyl nitrite is more 

 powerful than butyl nitrite, butyl than propyl, and so on, 

 methyl being the weakest of all. 



The order in which the paraffinic nitrites reduce blood 

 pressure in amount is somewhat, though not quite the 

 same, as that in which they accelerate the pulse, but 

 important exceptions occur, especially in the case of 

 methyl nitrite, which occupies a higher position as a 

 pressure reducing agent than it does as a pulse accelerator. 

 On the other hind, as regards duration of subnormal 

 pressure, the order is quite altered, the nitrites which 

 depress blood pressure to the greatest extent acting for 

 the most part for the shortest time. 



The authors have also endeavoured to determine the 

 comparative influence of the various nitrites on striated 

 muscle by exposing the excised gastrocnemius and triceps 

 muscles of frogs to equal quantities of their vapours, and 

 recording the extent and duration of contraction produced 

 with or without electric stimulation. This method is 

 open to the objection that hydrolysis of nitrite vapours 

 occurs very rapidly in the presence of aqueous vapour, 

 nitrous acid being produced. Now, muscle tissue is very 

 susceptible to the influence of acids, and it seems by no 

 means certain that the contractions recorded may not 

 have been in part, at least, due to the acid evolved from 

 the nitrite decomposition. With one exception (propyl 

 nitrite) it was noted that the nitrites with low molecular 

 weight were the least powerful in causing muscle 

 contraction, but they acted for the longest time. 



Concerning the effects which constitution of the 

 molecule apart from composition has, it was noted 

 throughout that when the effects of primary, secondary, 

 and tertiaiy nitrites having the same composition were 

 compared, the secondary nitrite was found to have a more 

 powerful influence on pulse acceleration, blood pressure, 

 and muscular contraction than the primary, and the 

 tertiary than the secondary. 



The fact that the acceleration of the heart caused by 

 the various fatty nitrites increases with their molecular 

 weight indicates, as the authors justly assume, that the 

 quickening action on the pulse cannot be simply con- 

 ditioned by the amount ot nitroxyl in their molecules, 

 even though it mav be true that the nitroxyl group itself 

 quickens the heart's action, for the molecule of methyl 

 nitrite, which is the least etTective, contains the largest 

 amount of NO..., whilst that of amyl nitrite, which most 

 powerfully accelerates the heart's action, contains less 

 NO.i than any of the other nitrites examined. .\ similar 

 conclusion is drawn with regard to the influence of the 



NO. I 30 I, VOL. 50] 



nitroxyl element in causing lowered blood pressure. It 

 is further pointed out, that the preponderance of 

 the hydrocarbon molecules in the higher nitrites is 

 not necessarily the cause of their increased influence in 

 quickening the pulse and lowering pressure. There 

 are other possible causes. After considering some of 

 these the authors express their opinion that the more 

 marked effect of the nitrites having the largest molecules 

 but containing the smallest amount of NOo is due to 

 their decreased chemical stability. They incline appar- 

 ently to the view that the actual molecules of the 

 paraffinic nitrites do not accelerate the heart's action and 

 lower tension, and give reasons for believing that they 

 may actually retard the rapidity of the heart's beat. 

 When, however, the molecule is broken up, the nitrite 

 element becomes active, entering, perhaps, into loose 

 combination with haemoglobin and certain tissues before 

 it is finally oxidised and eliminated. 



The lower combinations, such as ethyl and methyl, 

 being, as they suppose, least easily broken up, exercise 

 least power ; on the other hand, for the same reason they 

 act for a longer time, both in lowering tension and con- 

 tracting striated muscle. 



To the greater instability of secondary as compared 

 with primary, and of tertiary as compared with secondary 

 nitrites, they attribute their respectively greater power, 

 rather than to the fact that in the secondary and tertiary 

 compounds one and two methyl groups are respectively 

 attached to the carbon combination of the nitroxyl 

 group. Much remains to be done before the inferences 

 drawn from the elaborate investigations, the results of 

 which have been presented to the Royal Society, can be 

 regarded as defi.iitely proved ; but this paper adds, in an 

 important manner, not only to our knowledge of the action 

 of the nitrites, but to our comprehension of the manner in 

 which chemical agents influence the tissues, and become 

 of therapeutic value. 



THE LA TE PROFESSOR J. P. COOKE. 



THE death of Prof. J. P. Cooke was briefly announced 

 in these columns on September 13. The following 

 particulars, for which we are indebted to an obituary 

 notice in the Tribune of Cambridge, U.S..\., will be 

 read with melancholy interest by the scientific world : — 



Josiah Parsons Cooke was born in Boston, October 12, 

 1827. He was prepared in the Boston schools, and 

 entered Harvard College in 1S45, graduating three years 

 later. In the following year he was appointed an 

 instructor, and, in 1S51, Erving professor of mineralogv 

 and chemistry, and director of the chemical laboratory 

 of Harvard University, a post he held until his death. 



At the time Prof Cooke entered upon his duties as 

 head of the chemical department at Harvard, the 

 methods of instruction were of the most rudimentary 

 sort. Students in chemistry were required only to hear 

 so many lectures ; work in the laboratory was thought 

 unnecessary, its place being taken by the few experiments 

 which the lecturer saw fit to perform before his classes. 

 Now the chemistry courses at Harvard, as at all other 

 American colleges, consist almost entirely of laboratory 

 work. The credit for this change is due very largely to 

 Prof Cooke. 



Prof Cooke was made an LL.D. by the University of 

 Cambridge in 1SS2, and received the same degree from 

 Harvard in 1S89. He was a Fellow of the American 

 Academy and a Member of the National .\cademy of 

 Science. He was a popular lecturer, and delivered 

 several courses at the Lowell Institute, one of the best- 

 remembered being that given in 1S87 on the " Neces- 

 sary Limitations of Scientific Thought." 



He was the author of a number of books, pamphlets, 

 and scientific papers. Perhaps the best known of his 



