168 A WORD MORE ON THE " AGUE PLANT." 



followed by a "chlorogonimic " gonidial layer enclosed in a spongy 

 indistinctly cellular mass, whilst further inwards towards the middle 

 there occurred an irregularly interwoven fibrous layer, some of 

 the threads of which ended blind towards the hollow centre of the 

 " Botrydium-plant." He went further, and amongst those 

 examples of a chestnut-brown colour he detected apothecia, with 

 8-spored theca?, paraphyses none, spores colourless, filled with deli- 

 cate plasma, elongato-elliptic ; furthermore he found spermogonia, 

 with spermatia. But these examples did not satisfy Itzigsohn, 

 and he obtained, through friends, from Frankfort and Eichstadt, 

 examples fully developed, which, he says, satisfied him at last that 

 the plant passing at home with him as Botrydium was but the 

 undeveloped state of Tballoidima vesiculare (Hoffm.) Massal ; 

 {Lecidea vesiculare, Auct.). Still, he adds, he would reserve his 

 final judgment until he succeeded in obtaining fresh material for 

 the more exact examination of the common Botrydium form, 

 though he could entertain but little doubt but that " the unde- 

 veloped Tballoidima is perfectly identical with the plant figuring 

 amongst phycologists as Botrydium Wallrothi." 



It appears, then, that Itzigsohn's statements were after all, in 

 the present case, scarcely worth waiting for ; it cannot be doubted 

 that, though possessing some amount of outward resemblance, these 

 are two plants essentially distinct — it would seem pretty certain 

 that not even a Schwendener would claim Hydrogastrum as the 

 " gonidia-former," in any modified manner, of " Lecidea vesi- 

 culare;" but whether Itzigsohn ever investigated the matter any 

 further is unknown to me. 



On reading over the more recent description of the " Ague 

 Plant" communicated by Dr. Bartlett to the " Chicago Society of 

 Physicians and Surgeons" (see " Grevillea," No. 21, March, 1874, 

 p. 142), one sees how fairly it tallies with the known characters of 

 Hydrogastrum (see also Parfitt in " Grevillea," No. 7, January, 

 1873, p. 103), but it is undoubtedly surprising how he and the 

 American observers of the Society referred to (loc. cit.) failed to 

 perceive the identity of the organism in question, one which finds 

 a place in so many botanical text-books, both by figure and 

 description, as well as on lecture- diagrams, as a noteworthy 

 example of a single-celled independent plant, and at the same time 

 endowed with the power to become copiously ramified, so to speak, 

 "root," "stem," and serial portion combined in one "cell" only. 

 I venture to think it hardly less surprising to find this seemingly 

 so passive and inert little chlorophyllaceous alga, met with, in 

 suitable situations, all over Europe, gravely tried and found guilty, 

 on so. slender evidence, of being the atrocious " cause of the ague." 



In the mud-samples so kindly forwarded by the Editor, there 

 occurred some fragmentary examples of a plant wholly different 

 from the foregoing — so small in quantity as to be quite invisible to 

 the unassisted eye — but which disclosed itself amongst the debris 



