NOTICES OF BOOKS AND MEMOIKS. 123 



Das Microgonidium. Ein Beitray zur Kemtniss dvs Wahren Wesens 



der Flechten. Von Dr. Arthur Minks. Basel, Genf, Lyon, 

 H. George's Verlag. 1879. 



o~ ~ • — — & 



The subject of the dual nature of lichens is one the approaches 

 to which are so carefully watched, that to say anything about it is 

 almost equal to a conflict in which language, not only personal but 

 violent, is the favourite weapon. The author of the above work 

 does not depart from this mode of discussion until he has had his 

 say. He writes the " epitaph " of the Schwendenerian doctrine, 

 and then calls on mycologists, algologists, and his brother licheno- 

 logists to extend their hands to work out in quiet the solution of 

 the difficulties of the question. After reading his book, with the 

 hand of friendship outstretched, it is impossible to see that any 

 particular difficulty remains. 



Shortly stated, Dr. Minks 1 s offspring is a theory, backed by his 

 observations and controversial remarks, that microgonidia, which 

 are ultimately transformed into gonidia, exist spontaneously in the 

 hyphae, rhizines, cortical cells, paraphyses, thecae, and in the 

 spores and spermatia (!) of lichens. Thus furnished, these organs 

 are, as will easily be seen, equal to the necessities of vegetable life. 

 The Sclnvendenerian doctrine, as at first announced, may have 

 been startling, and the difficulties to be overcome in its proof hard 

 to dispel ; but it must pale in its demand for credence beside the 

 statement that "spermatia are not cells, but compound bodies 

 composed of cells.' ' This is perhaps the extremity to which we 

 are asked to go ; but it requires small knowledge of the subject to 

 uphold the assertion that it differs not in nature, but only in 

 degree, from these other propositions offered for our acceptance. 



The difficulties attending the manipulation of objects under 

 such high powers of the microscope as Dr. Minks has used in these 

 researches are well known in their effects to all microscopists ; and 

 it is very unw 7 ise to throw stones when an error is the result of 

 jaded or defective powers of vision under such trying conditions. 

 But in this case of Dr. Minks's microgonidia we have to contem- 

 plate not an isolated error, nor a small group of errors but a long 

 series of obseivations for which the word inaccurate furnishes a 

 feeble description. Many of the bodies described, such as micro- 

 gonidia in the spores and spermatia, are, we venture to assert, 

 without existence in such situations. How such errors may have 

 arisen it is not for us to explain ; but all who have followed the 

 literature of the subject wall recal the observations of Dr. Stabl on 

 the hymenial gonidia as suggesting the most probable solution. 

 The small hymenial gonidia wilich occur in the interstitial spaces 

 °f the apothecia of many lichens are the offspring of the ordinary 

 gonidia (thallus-gonidia), and have been carried up in the hymenium 

 by the growth of its hyphae. When the ascospores are emitted 

 from the apothecia, the hymenial gonidia are cast out also, and, 

 tailing in the nieghbourhood of the ascospores, are many of them 

 enveloped by the germinating filaments proceeding from the spores, 

 when the conditions are favourable for growth, Along with the 



