t6 



NA TURE 



[November i, 1900 



direct successor of his celebrated compatriot, Alfonso Borelli, 

 who, in 1653, discovered in Naples the irritability of the anthers 

 of Centaurea, and of other Cynarese. In his essay, "Del Moto 

 e della Irritabilita dei Vegetabili," published in 1789, Cirillo 

 briefly describes what was then known of the sleep of plants, of 

 the movements of the leaf blade of Dionoea muscipula, and of 

 the fly-trap concealed in the flowers of Aposytium androsaemi- 

 foliuin, a plant then lately studied by Francesco Bartolozzi in 

 Milan. ' Cirillo quotes Linnceus' description of the movements 

 of the Hedysaruin gyratts, first discovered by Pohl in 1779. 

 After describing the irritability of the stamens of the Cynareae, 

 the gradual sensitiveness of the flowers of Verbascum to shocks, 

 and the recent observations of Duhamel and of others on the 

 stamens of Berberis, and of Parietaris officinale, Cirillo goes on 

 to describe his own discoveries of irritability in Forsckohlca 

 tenacissima, -sjnA in the common nettle, Urtica dioica. "The 

 study of the very complex fructification of the first plant 

 (Forsckohlea) having revealed to me the spiral structure of the 

 filaments, similar to those of Parietaria, I was led to verify 

 whether these filaments also possessed irritability. It is of great 

 interest to observe in the netlle.during the warmer morning hours, 

 how the male flowers open abruptly, and suddenly burst open 

 their well-closed anthers, that eject abundant fertilising dust."^ 



These observations brought Cirillo to believe that the " mar- 

 vellous irritability of the sensitive plant, as well as the elasticity 

 in the stamens of flowers, must be partly due to the spiral struc- 

 ture of the organs in which the contractions take place, chiefly, 

 however, to the very frequent articulations of which these parts, 

 so mobile and so irritable, are essentially composed." 



Hedwig had in these years opened the way to the knowledge 

 of mosses ; and Cirillo again observed cases of irritability and 

 elasticity in the capsules of mosses and in the filaments they 

 contain, the articulated structure and the spiral form of which 

 again confirmed his opinion on the mechanism of plant 

 movement.-'' 



In studying the sensitive plant, Cirillo points out the enlarge- 

 ment at the insertion of each leaf; and observing what he 

 believed to be a spiral structure within this "tubercle-like 

 body," suspects a connection between the spiral structure and 

 leaf-movement. Comparing the Mimosa ptidica with the 

 Mimosa glatua, Cirillo finds that the great difference in their 

 sensitiveness corresponds with the different size and develop- 

 ment of the articulations containing the spiral structure. This 

 spiral structure corresponds, of course, with the fibro-vascular 

 bundle inside the pulvinus, the motor organ, in which, as we now 

 know, the sap tension suddenly sinks at every cause of irritation.* 

 Following the ideas of Haller, the first to have a notion of 

 protoplasm as the physical basis of life, Cirillo believes that the 

 seat of irritability and of life, both in animals and in plants, must 

 be in mucilaginous substances. Thus he points out that in 

 plants "glutinous principles" are commonly met with which 

 must be the seat of motion, of contraction, and of irritability. 

 Curiously enough, as an example of this glutinous principle, 

 Cirillo gives the " elastic resin now used so extensively" ex- 

 tracted from the sap oi Jatropha elastica, and existing, as he 

 observes, in many other plants. In that time, when only impure 

 rubber was in commerce, it had been observed that this sub- 

 stance, besides strongly-smelling empyrheumatic products, 

 yielded ammonia by distillation ; it was therefore generally con- 

 sidered of the same nature as glutinous animal substances.' 



1 Fr. Bartolozzi, " .'^opra la qualilk che hanno fiori della pi.-'nta delta 

 Apocynum Androsaemifolium di prendere le mosche, con una osservazione 

 nuova sulla fecondazione delle piante," OpuscoH Scelti ii. (Milano, 1779, 

 p. 103 ; and iv. 1787, p. 73). 



^ Besides G. B. Dal Covolo, " Discorso della irritabilita di alcuni fiori, 

 nuovamente scoperta " (Firenze, 1764), compare with the observations of 

 contemporary botanists — G. E. Smith in England, and Des Fontaines in 

 France. An abridgment of these observations was published in Italian at 

 Milan: Des Fontaines, " SuU' Irritabilita degli organi sessuali di molte 

 piante," Opuscoli Scelti x. 1787, p. 417 ; G. G. Smith, " Sopra la irritabilita 

 dei vegetabili," Op. Seek. xi. 1788, p. 379. 



3 See also Antonio Barba, '' Osservazioni sopra la generazione dei 

 Muschi," Op. Scelt. v. 1782, p. 128. Barba was a pupil of Cirillo and of 

 Della Torre. 



■* See also Andrea CoTiparetti, " Nouvelles Recherches sur la Structure 

 organisee relativement a la cause desmouvements de la sensitive commune' 

 (Mhit. Acad, de Turin, 1790)- 



5 It is interesting to remember that in those days, in London, Tiberio 

 Cavallo was first beginning to prepare india-rubber tubing for scientific 

 use, the tubes being made from an ethereal solution of the india-rubber. 

 See Faujas St. Fond, " Su alcune arti utili, tratte daun viaggio in Inghil- 

 terra, in Scozia, e alle Isole Ebridi," Op. Scelt. xx. 1797, p. 60. 



For the first applications of india-rubber in making waterproof cloth, &c., 

 and (or a description of Grossard's method of making india-rubber tubes, 

 see Cervantes, '' Resina Elastica," Op Scelt. xxi. 1798, p. 97. 



NO. 1 61 8, VOL. 63] 



The researches of Hunter, showing the connection between 

 nerve-action and electricity in the torpedo, and the experiments 

 that Cirillo's friend Italisckhi was making in Naples on the 

 electrical organ of the torpedo, brought Cirillo to believe that 

 there must be some special connection between electricity and the 

 action of nerves, and in general with all manifestations of irrita- 

 bility. As is well known, that was an active period of re- 

 search on the torpedo : suffice it to record the names of Walsh, 

 Pringle, Spallanzani, Soave. At Naples, in 1784, Domenico 

 Cotugno accidentally received an electric shock in vivisecting a 

 young mouse : this on the eve of Luigi Galvani's discoveries in 

 animal electricity. This was also the period of greater fervour 

 in experimenting upon the influence of electricity on vegetation. 

 These experiments were chiefly carried out by Achard in Ger- 

 many, Berthelon in France, Toaldo, Gardini and Vassalli in 

 Italy and by Ingen-Housz in England. Vassalli and Rossi 

 were soon to show the excitability of the sensitive plant under 

 electric action.^ 



The connection of the chemical action of atmospheric air 

 with respiration, and with all forms of animal and vegetable 

 motion, was evidently in the mind of Cirillo. Indeed, for many 

 years scientific research in Italy, both on animal and vegetable 

 Hfe, had been discovering more and more this connection, pre- 

 paring the way to modern knowledge of respiration and of the 

 origin of vital heat and of vital motion. 



Fracassati, in 1665, had observed the change of colour in 

 blood when shaken up in air. The experiments of John Mayow, 

 the pre-discoverer, if the term may be used, of oxygen, were 

 perhaps better known and appreciated in Italy than in England, 

 through Ludovico Barbieri, of Imola, who translated and ex- 

 tended the work of the English chemist. Barbieri observed 

 that the bright colour of arterial blood must be due to impreg- 

 nation with nitro-aerial spirit ; and he showed, by experiments 

 on the transfusion of blood into an animal prevented from 

 breathing, the truth of Mayow's teaching, that atmospheric 

 nitro-aerial spirit, fixed in the blood, sustains life and, as in 

 the case of the flame, produces heat. Barbieri also taught that 

 the nitro-aerial spirit of the air causes the germination of seeds 

 and sustains the life of plants.^ 



Hales, during the first part of the eighteenth century, had 

 shown how plants suffer when enclosed in gases other than air, 

 as the "air" extracted by distillation from Newcastle coal. 

 Bonnet and Duhamel observed subsequently that leaves perish 

 when covered with oil. But to Buonaventura Corti, the dis- 

 coverer of protoplasmatic movements in the vegetable cell, is 

 due the first exact proof of respiration in plants. Corti showed, 

 in a series of experiments, that when air is excluded from the 

 vegetable cell all circulation of the cell -sap is arrested : "now 

 that we have shown," he observes, " that the circulation of the 

 sap of the Chara is arrested when in vacuo, we readily under- 

 stand why all plants perish without air, and why seeds 

 cannot germinate without air, or perish shortly after sprout- 

 ing."^ In those days, in 1773, Francesco Cigna, in Turin, 

 was again proving the action of air upon the colour of 

 blood, and the influence of blood upon the properties of air. 

 Cigna's experiments were repeated with greater exactitude, after 

 the discovery of vital air, by Priestley, who showed that vital air, 

 i.e. oxygen, causes the blood to brighten, while its colour 

 deadens in contact with other gases. The discoveries of Priestley 

 were followed, in 1779, by Adair Crawford's theory and experi- 

 ments on respiration and animal heat.^ According to Crawford, 

 the latent heat of atmospheric air gradually becomes perceptible 

 as animal heat, while the air absorbed through the lungs gets 

 mixed and retained in the blood, which yields its phlogiston to 

 the atmosphere. Crawford held that vegetable matter is elabo- 

 rated, and becomes charged with phlogiston, under the action of 

 solar rays ; whilst during the combustion of vegetable matter 

 phlogiston is again yielded up to the atmosphere and fire gener- 

 ated, in the same way blood generates heat, while phlogisticat- 

 ing expired air. Vegetables again, growing under the influence 



1 Cotugno's observations on the electrical mouse are described in a letter 

 to Vivenzio. See Tiberio Cavallo, " Teoria e Pratica dell' Elettricitk 

 Medica" (Napoli, 1784, p. 157). This is an Italian translation by Vivenzio; 

 the original English work was published by Cavallo in London, in 1780. 



2 " Planta a spiritu nitro-aereo prima vitae stamina suscipit," wrote Bar- 

 bieri in 1680. See Salvigni, " Ragionamento sopra alcune dottrine chimiche 

 di Giovanni Mayow e di Ludovico Barbieri " (Bologna, i8i6). 



3 B, Corti, "Osservazioni microscopiche sulla Tremella e sulla circo- 

 lazione del fluids in una piantaacquajuola " (Lucca, 1784, p. 191). 



* An Italian abridgment of Crawford's paper was published very soon 

 after its appearance in England: Adair Crawford, " Sul calore animale e 

 suir infiammazione deicorpi combustibili," Opuscoli Scelti iii. 1780, p. 73. 



