HARDWICKE'S SCIEJSl CE-GOSSIP. 



229 



dermal granules or spinous tubercles, and character- 

 ised by the absence of a caudal spine. But, although 

 these fishes exist at the present day in considerable 

 nambers and have a remarkably wide geographical 

 range, very little is known of their past history. The 

 Lower Lias of Lyme Regis yields some fragmentary 

 fossils (Arthropterus) that have been thought to be 

 properly placed here, and a few doubtful indications 

 of other members of the family have been noticed in 

 later Mesozoic formations, but among British rocks, 

 the Pliocene Crags appear to be the only beds 

 containing reliable evidence, and this consists merely 

 in detached dermal tubercles. The fossil tubercles 

 (fig. 163) resemble so closely those disposed upon the 

 back of the recent Raja (vol. xx. fig. 101, p. 1 73) — 

 the genus to which the Common Skates and Thorn- 

 backs belong — that they have been referred to it by 

 Agassiz, and distinguished under the specific name of 

 R. antiqua, 



Trygonid.e. 



So far as known, the "Sting- Rays" are un- 

 represented among British fossils, and do not appear 

 to have been met with on the Continent in strata of 

 an earlier date than the Eocene. These forms clearly 

 exhibit the more important characters of the family as 

 at present developed, and belong to still-existing 



genera. 



{To be continued.) 



ERYTHROXYLON COCA. 

 By H. Whittaker, F.S.Sc. 



A LEADING article in the " Globe" of April 22 

 brings the Erythroxylon coca under our notice. 

 The occasion of this article was an incident in a 

 lecture at Madras by Dr. Bidie ; viz., that, in the last 

 famine, he had noticed many of the suffering natives 

 eating considerable quantities of devadru, a plant 

 which belongs to the same family as Eiythroxylon 

 coca. It appears that of late this plant has attracted 

 the attention of medical men, who have, as the 

 "Globe" remarks, " recognised the merits of cocaine 

 (the active principle of the herb) as an anaesthetic, 

 more especially in ophthalmic operations." Any 

 medicine that has the property of subduing the 

 intensity of pain attendant upon perhaps all surgical 

 operations, is sure to be welcomed, and will un- 

 doubtedly receive that searching examination and 

 keen criticism it is in the power of the medical pro- 

 fession to bestow. 



Should the researches of eminent men confirm the 

 opinion which is at present held by some touching the 

 therapeutical value of the coca, doubtless it would be 

 a good thing, not only for the profession, but also for 

 the planters in India. It appears that the Erythroxy- 

 lon motiogymim (the scientific name for devadru) is a 

 native of Cuddapah, in India, and the presumption is 



that the E>ythroxylon coca may "easily be grown 

 there with success." 



The cultivation of the coca would be an immense 

 boon to these people, whose realisations from coffee- 

 planting are not as great as formerly. 



Up to the present, however, opinions of experi- 

 mentalists have not, unfortunately, been unanimous. 

 Glowing accounts are given by some of its wonderful 

 sustaining power, of the pleasant sensations or 

 phantasmagoria produced by its internal use, and of 

 its tonic influence on the nervous system, while others 

 derive no such sensations, not " even that exhilaration 

 which is produced by a draught of spring water." 

 The testimonies of those who have made the coca 

 the subject of personal study and experiment are 

 diametrically opposed to each other. Professor 

 Brown says: "It stimulates the stomach and 

 promotes digestion. In large doses it augments 

 animal heat and accelerates the pulse and respiration. 

 It induces slight constipation. In moderate doses 

 (one to four drachms) it stimulates the nervous 

 system, so as to render it more tolerant of muscular 

 fatigue. In larger doses it gives rise to hallucination 

 and true delirium. Its most precious property is that 

 of inducing the most pleasant visions without any 

 subsequent depression of the nervous energies. 

 Probably it diminishes some of the secretions." He 

 evidently considers it of the greatest value in nervous 

 diseases, on account of the tonic power it apparently 

 possesses. 



It is said that the Indians, after chewing a few 

 leaves of the coca plant, can perform an extraordinary 

 amount of labour. They also take it in very large 

 doses, which act as an intoxicant, producing somewhat 

 the same effect as opium or hasheesh. The pedestrian 

 Weston is said to have used this plant, probably in 

 infusion, but the writer is under the impression that 

 this rumour has been contradicted. 



Professor Bentley, F.LS., in his excellent work on 

 Botany, says : " The leaves of this plant are much 

 used by the natives of Peru, and some other parts of 

 South America, as a masticatory. The Peruvian 

 Indians have always ascribed to the coca the most 

 extraordinary virtues. Thus, they believe that it 

 lessens the desire and the necessity for ordinary food, 

 and, in fact, that it may be considered as almost a 

 substitute for food . . . Dr. "Weddell, however, speaks 

 far less highly of its virtues. He states that it does 

 not satisfy the appetite, but it merely enables those 

 who chew it to support abstinence for a length of time 

 without a feeling of hunger or weakness ... In 

 France a tonic wine is made from the leaves. Coca 

 is deserving of an extended trial in this country as a 

 medicinal agent," &c. 



The writer experimented with an infusion of the 

 leaves, but perceived none of the effects usually 

 ascribed to the drug. This diversity of opinion may 

 perhaps be explained by the following considera- 

 tions. 



