iv.] YEAST. 



nitrogenous " animal " substance ; and that such a sub- 

 stance is contained in all ferments. Before him, Fabroni 

 and Fourcroy speak of the " vegeto-animal " matter of 

 yeast. In 1844 Mulder endeavoured to demonstrate 

 that a peculiar substance, which he called "protein/' 

 was essentially characteristic of living matter. 

 In 1846, Payen writes : 



" En fin, une loi sans exception me semble apparaitre dans les faits 

 nombreux que j'ai observes et conduire a envisager sous un nouveau 

 jour la vie ve*ge"tale ; si je ne m'abuse, tout ce que dans les tissus 

 vegetaux la vue directe oil amplifiee nous perrnet de discerner sous la 

 forme de cellules et de vaisseaux, ne represente autre chose que les 

 enveloppes protectrices, les reservoirs et les conduits, a 1'aide desquuls 

 les corps anirnes qui les secretent et les fagonnent, se logent, 

 puisent et charrient leurs aliments, deposent et isolent les matieres 

 excre"tees." 



And again : 



" Afin de completer aujourd'hui 1'enonce du fait ge"n6ral, je rappel- 

 lerai que les corps, doue des fonctions accomplies dans les tissus des 

 plantes, sont forme's des elements qui constituent, en proportion peu 

 variable, les organismes animaux; qu'ainsi Ton est conduit a reconnaitre 

 une immense unite de composition e*lementaire dans tous les corps 

 vivants de la nature." 1 



In the year (1846) in which these remarkable passages 

 were published, the eminent German botanist, Von Mohl, 

 invented the word " protoplasm/' as a name for one por- 

 tion of those nitrogenous contents of the cells of living 

 plants, the close chemical resemblance of which to the 

 essential constituents of living animals is so strongly 

 indicated by Payen. And through the twenty-five years 

 that have passed, since the matter of life was first called 

 protoplasm, a host of investigators, among whom Cohn, 

 Max Schulze, and Ktihne must be named as leaders, have 

 accumulated evidence, morphological, physiological, and 



1 "Mem. sur les Developpements des V^getaux," &c. -"Mem. PnJsenWes." 

 ix. 1846. 



