OF THE NEMATOIDS, PARASITIC AND FEEE. 61S 



swarming with myriads of minute monads, to which the next day may be added larger 

 infusory animalcules ; together, these proceed rapidly with the work of demolition, and 

 in the course of a few days leave only the chitinous integumentary sheath of the Nema- 

 toid as the remnant of their feast. 



The revival of animals after complete desiccation was first observed amongst the 

 Rotifera by Leeuwexhoek in 1701, and his observations were subsequently repeated by 

 many other naturalists during the next half century, the principal of whom were Hill, 

 Baker, Fontana, Gozfi, Corti, Otto Muller, and the Abbj5 Spallanzanl The discoveiy, 

 by Neediiam, in 1743 of the young Anguillulse in what appeared to be diseased gi'ains of 

 wheat*, added another animal to the list of those possessing this remarkable power of 

 reviviscence after prolonged periods of desiccation ; and very shortly after this the number 

 was still further increased by SPALLAlfZANl discovering that, in addition to the Rotifera 

 in tufts of moss, there were certain Anguillulse and arachnidal animals (" Sloths ") found 

 in the same situation, all of which were endowed with a similar tenacity of life. 



One of the most interesting facts that has yet been made known concerning the so- 

 called Vibrio tritici was ascertained by Baker. He discovered that some of these 

 animals contained in diseased wheat, given to him by Needham in 1744, still possessed 

 the power of resuming all their vital manifestations, after immersion in water, in 1771 ; 

 that is to say, after a period of twenty-seven yearsf . This is the longest period on record, 

 and several observers have failed to restore them after much shorter intervals. Thus 

 with wheat of a certain year's growth, Bauer $ could not revive these animals after five 

 years and eight months ; whilst with that of another year he met with the same failure 

 after six years and one month. My friend Mr. W. H. Ince tells me that he has seen 

 them revive from specimens of wheat which had been kept " about twenty years." The 

 varying periods during which these Nematoids retain this power of reviviscence in all 

 probability depends veiy much upon the manner in which the "galls" have been preserved 



* The Nematoid (Ti/lenchtts tritici) producing this disease of 'wheat, known as "purples" or " ear-cockle," is 

 not contained in a real seed but in a gall-like growth replacing this. For further partictilars on tliis subject 

 see Dataixe's ' Eechcrchcs sur I'Anguillule dii ble niellc,' p. 20, and the " Monograph on the Anguillulidtc," 

 Trans, of Linn. Soe. vol. xxv. p. 87. 



t Lettrc de Needham en rdponse au memoirc de Eoffredi, dans ' Joum. de Physiq.' t. v. p. 227, 1775. At one 

 time Spallaxzaxi believed that these vrero not real animals, but merely " filets allonges ct mis en mouvement 

 par le fluide qui les penetre" (Nouv. PkCchcrch. sur les decouv. Microscop. &c., Annot. par Needham, part 1. 

 p. 25, Paris, 1769) ; in this boUcf he was for a time followed by Needham. Both Okejj and RuDOLPni (Grundr. 

 der Physiolog. 8vo, 1821-27) deny the fact of the revival of animals after desiccation, whilst Bory de Saixt- 

 ViNCENT and Dueics deny its occurrence in the Vibrio tritici. Even Diesing, writing as late as 1851, makes 

 the following statement on this subject : — " Animalcula exsiecata, iterum humectata post annos reviviseere narrant 

 eel. Batjee et Hj:nslow, phenomenon rectius forsan motu moleculari exjalicandum" (Syst. Helminth, t. ii. p. 132). 

 And even amongst those who admit the fact of the reality of the powers possessed by these animals of recovering 

 after periods of desiccation, most various statements have been made by recent writers ; thus Cobbold states that 

 they are capable of recovering after " two or three years " of desiccation, whilst Professor Aitkek (So. and Prac. 

 of Med. 1SG3, vol. iii. p. 126) even puts the period as low as from " four to seven days." 



i Philosophical Transactions, 1822. 



