1218 Journal of Applied Microscopy 



nature in the filtered chyme, in sufficient quantity to interfere with the result 

 desired. For instance, to show that ordinary saline matters and waste that 

 might be present in the stomach could not cause a precipitate, we need only 

 add phospho-molybdic acid to urine, when we find a reassuring absence of any 

 precipitation. 



You will ask what practical result we can derive from such an examination. 

 The method is comparatively simple, and by it we can tell exactly how much 

 digestive work the stomach is accomplishing. In general, we shall find an 

 excess of lower forms of proteids in cases of subacidity and deficient formation 

 of ferments. For instance, in cancer, we should expect at least 2 per cent, of 

 acid albumin, probably as much albumose, and only 5 or 10 percent, of peptone, 

 by bulk. We must also bear in mind that an excess of an end-product may 

 mean either unusually good digestion or poor absorption. a. l. b. 



GENERAL PHYSIOLOGY. 



Raymond Pearl. 



Books and papers for review should be sent to Raymond Pearl, Zoological 

 Laboratory, University of Michigan, Ann Arbor, Mich. 



Driesch, H. Studien liber das Regulationsver- I" this paper are collected the results 



mogen der Organismen. 5. Ergiinzende of several sets of experiments on the 



Beobachtungen an Tubularia. Arch. Ent- 1 1 ■ , t-. , 7 • , , 



wick.-Mech. 11 : i8i;-2o6 igoi. hydroid lubiilana inesembryant/iemum, 



all having as a general problem the 

 regulatory processes of the organism. The first point considered is the number 

 of tentacles formed in successive oral reparations. In the experiments the polyps 

 were cut off and formed again five times in succession. In each successive 

 reparation the average number of tentacles is less than in the preceding one. 

 The difference in the number of tentacles between the original polyp and the 

 individual resulting from the first reparation is greater than that between the 

 individuals of any of the succeeding reparations. It is believed that this differ- 

 ence between the original hydranth and the subsequent formations is due to 

 differences in nutritive conditions in the two cases. The second point deter- 

 mined was that fewer tentacles are formed on the polyp at the oral end of an 

 aboral piece of stem than on the oral polyp of an oral piece, and that the number 

 of tentacles of a polyp formed at the aboral end of an oral piece was less than in 

 the case of oral polyps of either piece. From experiments with dififerent lengths 

 of stems it appears that, the longer the piece of stem is, the more tentacles the 

 polyp formed on it has. The author repeats his former conclusion that the " red 

 substance " is the " means " by which the regulatory processes are effected in 

 Tubularia. All the facts of tentacle formation are explained as due to the greater 

 aggregation of this formative " red substance " at the oral end of any piece of 

 the hydroid, whether original or secondary (resulting from operation). The next 

 main topic of the paper is the healing of wounds in the perisarc. If the perisarc 

 is removed over a certain area of the coenosarc the wound heals very quickly. 



