88 



the attacks of an allied species in European 

 collections of CactaceEe (Hirscht, 1899). The 

 malady, which is referred to earlier in this report, 

 extends as far south as Mexico City. Mexicans 

 regard it as a serious disease, particularly where 

 Prickly-pears are growing in a more or less 

 crowded state. It is said to be more prevalent 

 during dry weather. 



Utilisation as Food for Man. 



Drs. Griffiths and Hare, in their paper on 

 "The Tuna as Food for Man" (1907 a), have 

 given an interesting account of the uses to which 

 Prickly-pear, especially the fruit, is put by the 

 Mexicans. The following is a summary of the 

 information contained in their article. 



The fruits or tunas form a very important 

 constituent of the diet of the poorer classes. Some 

 of the relatively spineless species of Prickly-pear, 

 known as "mansa" and related to 0. ficus-indica 

 naturalised in the Mediterranean region, receive a 

 certain amount of cultivation, which generally 

 consists of planting cuttings and protecting them 

 from cattle by surrounding the plants with a 

 fence or a hedge of spiny Opuntias or columnar 

 Cereus. Certain spiny forms, such as "Cardona" 

 — 0. streptacantha (an ally of our " Westwood 

 Pear") — are also propagated, as they yield a 

 fruit much appreciated by the Mexican. The 

 production of fruit is the first consideration, 

 stock-feed being secondary. 



The spinules are removed in various ways 

 and the skin or rind separated off as is done in 

 the Mediterranean littoral. In the case of certain 

 fruits (0. leucotricha) both pulp and rind are 

 eaten. Seeds are generally swallowed, though it 

 is recognised that those of the "mansas" cause 

 indigestion, while those of the "tapon" (0. 

 rohusta) may cause serious intestinal obstruction 

 which has been known to end fatally. The 

 "cardona" (0. sirepiacaniha) is said to be 

 the favourite as an article of diet, and there is 

 an absence of iU-effects after eating freely of it. 



Analyses of the fruit rind and pulp, as well 

 as of fruit from which the peel and seeds had 

 been removed, have been published by these 

 workers, nearly all the species examined being 

 from Mexico (pp. 15, 16, 32-42). It was found 

 that the Mexican samples averaged 9-53 per cent, 

 sugar, while the fruits which were analysed from 

 species growing in the United States averaged 

 5-61 per cent., certain Mexican species found 

 there in a naturalised state being included, their 

 inclusion considerably increasing the average 

 sugar content. Samples of indigenous Opuntias 

 from San Antonio, Texas, were found to average 

 less than 3 per cent. Amongst the Mexican 

 Prickly-pears examined were the "tuna ama- 

 rilla," "cardona," "chavena," and the fruit of 

 0. imhricata. The three first-named are allied to 

 the "Yellow Mexican" and "Westwood" pears 

 of Queensland, and the last-named species occurs 

 in parts of New South Wales and Queensland. 

 It may be remarked that practically no sugar 

 was found in fruits of 0. imhricata. 



In addition to those used in a fresh state, 

 vast quantities of Prickly-pear fruits or tunas 

 are dried for use. These are prepared mainly 

 from those of the cultivated species, since they 

 are larger and paler in colour, the popular ' ' ear- 

 donas" being less suitable as they are rather 



too small and possess too many spinules, and, 

 moreover, their red colour becomes altered to 

 black— regarded as an objection by the Mexi- 

 cans—during the process of drying. The fruits 

 are thinly peeled, and the remaining rind and 

 pulp is set out in the sun on a framework for 

 from ten to fifteen days, a yellow deposit of sugar 

 and mucilage forming on the outside as drying 

 progresses. They are then packed loosely in 

 crates for about six months to allow further 

 evaporation. The "tuna amarilla" is especially 

 suitable for drying on account of its size, flavour, 

 and sugar content. Dried tunas are used as food 

 after being cooked in a similar manner to the 

 ordinary dried fruits of commerce — e.g., apricots, 

 &c. 



Schumann (1899) in his account of various 

 ]\Iexican cacti mentions in many cases that the 

 fruit is edible. In addition to certain species of 

 Cereus, Pilocereus, EcMno cereus, and Phyllo- 

 cactus, the following Opuntias are mentioned: — 



Opuntia leucotricha — the durasnillo; 0. 

 ficus-indica, L. ; 0. streptacantha — the cardona; 

 and 0. rohusta, Wend— the tapona. In addition, 

 the fruits of certain species of Mamillaria (p. 

 570) are sold in Mexican markets under the name 

 Chilitos, on account of their resemblance to small 

 chillies (cayenne peppers). The fruits of Cereus 

 trigonus are recorded by Schumann (1903, p. 57) 

 as being used in Costa Rica. A. Weber (1902) 

 has referred to the high opinion which Mexicans 

 ihold regarding the durasniUo on account of the 

 flavour of the fruit. E. Gosselin, in 1904, briefly 

 described the fruits of eight Opuntias of Mexican 

 origin, grown in the French Riviera near Nice. 



In the Catalogue of the Darrah collection of 

 cacti in the Alexandra Park, Manchester, in 

 addition to those mentioned by Schumann, the 

 fruit of many other Mexican and Central Ameri- 

 can species of Cereus is said to be used for food. 



Prof. Hare (1911, p. 26) has stated that the 

 natives of Mexico and of South-Westem U.S.A. 

 make richly coloured preserves from the fruits of 

 0. dulcis, the evaporated juice containing from 

 30 to 60 per cent, of glucose, but apparently free 

 from pectin substances, since it will not jellify 

 unless it be mixed with plenty of other fruit- 

 juices rich in pectins. A preliminary account of 

 the alcohol precipitates from Prickly-pear fruit 

 pulp was published earlier by GrifiSths and Hare 

 (1907 a, p. 40). It was found that the average 

 amount in all the pulps examined was only -29 

 per cent., that in the rinds being about four 

 times as much — ^viz., 1-29 per cent, These authors 

 were unable to make jeUy from either the pulp 

 or the rind, there being apparently little, if any, 

 pectin present in the fruits. Forty per cent, of 

 the alcohol precipitate from the rind, and 25 per 

 cent, of that from the pulp, was found to consist 

 of ash. The ash from the whole fruit amounted 

 to about -29 per cent., whereas in the stems it 

 is very considerable, 33 per cent, of the dried 

 stem being found to consist of ash in one instance. 

 Salts of lime and potash constitute the greater 

 part of it, phosphates being very low, only 1-39 

 per cent of phosphoric acid being found as the 

 average of 28 samples examined. 



Roderiquez (1912, p. 207) has recently stated 

 that the amount of sugar in the fruit can be con- 

 siderably augmented by selection and good culti- 

 vation, and that it is possible to obtain a juice 

 with as much as 34 per cent, of sugar. 



