SCIENCE. 



[Vol. XXII. No. 544 



solved in 500 cubic centimetres of water, and then dilute sul- 

 phuric acid added till tbe hydrazoic acid was liberated. Tbe so- 

 lution was then distilled till the distillate ceased to give a precipi- 

 tate with silver nitrate. 



The distillate was then diluted to a definite volume and its 

 strength determined by titration with standard ammonia solution. 

 The yield of the acid was 87 per cent of the theoretical, 500 cubic 

 centimetres of nearly 4 per cent solution being obtained. 



A part of the acid solution was neutralized with potassium car- 

 bonate, and evaporated to crystallization. Beautiful, tabular, 

 transparent crystals of the potassium salt, KNj. were formed. 



The salts of hydrazoic acid, excepting tbe salts of the alkali 

 vnetals and the metals of the alkaline earths, are explosive. In 

 some respects the acid resemblts hydrochloric acid. With soluble 

 silver salts a white precipitate, AgN^, is formed. Lead acts sim- 

 ilarly. These salts explsde very violently when heated. 



The most remarkable propei'ty of hydrazoic acid and its soluble 

 salts is their physiological action. In this respect they resemble 

 the nitrite of amyl, CsHnNOa, having a marked influence upon 

 the action of the heart. Tbe author found by experiment that 

 one-tenth of a grain of tbe potassium salt, KNj, dissolved upon 

 the tongue (the resulting solution not being swallowed, but 

 ejected from the mouth) was sufficient to increase tbe pulse from 

 9G beats per minute to 153. This required only five minutes' time 

 after the dose was taken. This rate of heart-beat is not sustained, 

 however. A sudden and rapid reduction takes place, and ten 

 minutes after the dose was taken the heart was giving 60 feeble 

 beats per minute, making a total variation of 97 beats per minute. 

 Considering the fact that this effect was produced by the small 

 quantity of the substance which was absorbed by tbe mucous 

 membrane of the tongue, this property is certainly remarkable. 

 The vapors of the hydrazoic acid produce similar effects when 

 inhaled. 



The laboratory work reported in this article was performed in 

 the chemical laboratory of Cornell University; and the author 

 wishes to acknowledge that the success of the work was largely 

 due to the aid and direction given by Dr W. E. Orndorff. Thanks 

 are also due him for his kindness in reading and correcting the 

 ^manuscript. 



ON PROTOPTERUS ANNECTENS. 



EY DB. E. W. SHUFELDT, WASHINGTON, D.C. 



There has been very recently published in the Transactions of the 

 :Roval Irish Academy (Vol. XXX., Part III., pp 109-330, Plates 

 vii. to xvii) the long-delayed work of Professor W. N. Parker 

 of the University College, at Cardiff, Wales, " On the Anatomy 

 and Physiology of Protopterus annectens." Through the courtesy 

 of its author, a reprint of that most valuable quarto is now before 

 me, and it is my wish to write a brief notice here in regard to it. 

 The elaborate manner in which the Transactions of the Academy 

 are published is too well know to require remark, but in the 

 present instance it is impos-ible to pass this work without a word 

 u_pon the truly superb plates that illustrate it. These, some ten 

 in number, were chromo-lithographed by Professor Parkers 

 younger brother, M. P. Parker, and printed by West, Newman. 

 They present us with much of the anatomy and histology of 

 Protopterus, and are throughout perfect masterpieces of the kind, 

 and of the very highest order of merit. 



As is well known, this genus formerly was wvittea Lepidostren, 

 ■the South American species being L. paradoxa, and the African 

 •one L. annectens^' and among the first to pay any attention to it, 

 .of a reliable nature, vvas Sir Richard Owen, who, in 1839-1841, 



1 Dr. Gamher classifies them as follows: — 



Suborder III. Families. Genera. 



/ 1. Sirenld^, {^^P^.-HeTatolfut '"™'°^- 

 OBBEKII.— Ganoideil Dipnoi. J 3- Ctenododl- (Two extinct genera, Dip- 

 i J pteridEB ( terus and Heliodus. 



( ^ Phancro- J Extinct Plianci*pleuron. 

 V pleurldEB ( ^ 



And tie remarks ttrat " Two species are known, L. paradoxa, from the system 

 of tlie river Amazon, and L. (Protopterus) auneciens, which abounds In many 

 localities of the west -coast of Africa, is spread over the who;e of tropical 

 Africa, and in many districts of the central parts forms a regular article of 

 aiet." 



published bis "Description of Lepidosiren annectens" in the 

 Transactions of tbe Linnaaan Society of London (Vol XVIII.), 

 since which time naturalists have never ceased to furnish various 

 accounts of the biology of this extremely important form, but 

 usually based, as Professor Parker remarks, upon badly preserved 

 material. Our present author was far more fortunate as he bad 

 perfectly fresh specimens to work upon. Of these he has said in 

 his "Introduction," that "All my material, with tbe exception 

 of two specimens, purchased last autumn, were placed at my dis- 

 posal by Professor Wiedersbeim. These were received alive direct 

 from the neighborhood of the Gambia, and to Dr. J. Beard is due 

 the credit of having arranged for their transport. While in the 

 torpid condition about one hundred specimens had been dug out, 

 each surrounded by a clod of earth," and the clods were then 

 packed together in open crates. In Jhis manner they travelled 

 without harm, nearly all of them being alive and in a healthy 

 condition on their arrival in Freiburg. On being removed from 

 the clods, they were, by the kind permission of Professor Hilde- 

 brandt, placed in a large wire cage, sunk beneath the water in a 

 basin used for the culture of water plants in one of the hot-houses 

 of tbe Botanical Gardens, in which a constant temperature of 

 33.5° C. was maintained." ' . . . '• Protopterus lives probably to 

 a great age, and this supposition is supported by the samewhat 

 incredible statement of the natives mentioned by Stuhlmann, 

 that some specimens reach a length of six feet. From the obser- 

 vations of Hyrtl and Bischoff, it appears that Lepidosiren also 

 attains a large size, reaching, at any i-ate, three feet in length " 



(P 113)- 



It was found that Protopterus grows very rapidly, has great 

 vitality, and, although able to sustain fasts, is exceedingly vo- 

 racious, devouring all the abundant snails, earth-worms, and small 

 fish given them, and then killing and eating each other, making 

 it difficult in tbe extreme to preserve the specimens. 



Protopterus is most active at night, and appears to keep mostly 

 to the shallow water, where they move deliberately about on the 

 bottom, alternately using the peculiar limbs of either side, though 

 their movements do not seem to be guided by any strict regu- 

 larity. "Gray has compared these movements with those of a 

 Triton, and several other observers have noticed them. The 

 powerful tail forms a most efiScient organ for swimming rapidly 

 through tbe water." 



'' It is well known that Protopterus comes to tbe surface to breathe 

 at short intervals, and thus it is evident that the lungs perform 

 an important, if not the chief, part in respiration during the 

 active life of the animal. The air passes out again through the 

 opercular aperture, and the movements of the operculum itself 

 indicate the fact that bronchial as well as pulmonary respiration 

 takes place." 



Externally, the sexes present no characters whatever distin- 

 guishing them apart, and even in immature specimens it is diflS- 

 cult to tell ovary from testis. ^ 



In the present brief notice it will be impossible for us to even 

 abstract the positive advances Professor Parker has made for us 

 in our knowledge of both the anatomy and physiology of this in- 

 structive Dipnoan. He sums up handsomely on page 313, under 

 his " General Abstract, Summary of Chief Resti ts, and Conclu- 

 sions." 



His researches convince him that, although many points of 

 resemblance exist between Protopterus and certain Elasmobranchs 

 and Ganoids on the one hand, and on the other to some of the 

 lower Amphibians, it exhibits numerous distinctive characters of 

 its own, both primitive and specialized, and so, together with 

 Lepidosiren and Ceratodus, must be placed at a great distance 

 from either class. Further, he believes that the Dipnoi, as a 

 group, should not be retained among the fishes, still less among 

 the Amphibia. 



- To those less familiar with the habits of this extraordinary fl&h, I would 

 say that the species averages about four feet in length, and is an inhabitant 

 of the Gambia River in Africa. They bury themselves lu the mud during the 

 dry season, making a kind of nest in which they pass a period of torpidity. 

 Here they may remain for the best part of the year, but on the return of the 

 wet season resume again their aquatic mode of life. 



' In 1889, it will be remembered, Stuhlmanu also gave an interesting 

 count of Pro'.opterus, published in German. (.Berlin.) 



