PHYSIOLOGY OF THE INVERTEBRATA. 13 



took place. Therefore, both Eeinke and Mori support Baeyer's 

 theory that formic aldehyde is formed by chlorophyll under 

 the influence of light from the carbonic acid of the atmosphere 

 in the presence of water : 



fCO, = CO + 0) ^ fH 



1h,0 = H, + OJ ' ^ ICOH. 



Dr. Kretzschmar (^Mffei'mamw's Cantralhlatt fur Agrimdtur- 

 Chemie, 1882, p. 830), on the other hand, states that the 

 protoplasm of living and dead cells reduces silver from an 

 alkaUne solution of the salts of that metal, and so concludes 

 that this reagent fails to distinguish between living and dead 

 protoplasm. 



The author * has also shown that the alkaline solutions of 

 copper (cupric) and silver salts are reduced by both living 

 and dead protoplasm. In fact, these reagents fail to dis- 

 tiaguish between living and dead protoplasm, but these 

 investigations do not disjjrove Loew and Bokorny's idea that 

 protoplasm (i.e., living and dead) contains an aldehydic group 

 of elements ; but this particular group of elements is only one 

 of many combinations of elements forming the complex 

 molecule of albumin. 



When we study the decomposition of albumin (both animal 

 and vegetal) by the agency of different chemical reagents, 

 we begin to see that its chemical constitution is not repre- 

 sented by any simple group of elements. Many of the 

 substances found in the animal body are products of the 

 metabolism of protoplasm — e.g., urea (ONjH^O), creatine 

 (C^H,N302), creatinine (C^H^NjO), cholesterine (G^gR^fi^), uric 

 acid (C^H^NPa), guanin (C5H5N5O), leucin (OsH^NOs), tyrosin 

 (0,H,,N03), &c. 



Professor P. Schtitzenberger {Gomptes-Bendus, vol. 106, 

 p. 1407) has shown experimentally that when albumin is 

 boiled with barium hydroxide, it yields leucin, leucein, and 

 the products of hydration of urea and oxamide ; and Dr. W. 



* The Chemical News, vol. 48, p. 179 ; Journal of Boyal Microscopical 

 Society, 1884, p. 249 ; Journ. Chem. Soc. 1884, p. 202. 



