16 KAJSrSAS ACADE3IY OF SCIENCE. 



upon the body of the tissues, decomposing and sucking up the cell contents for its 

 own nourishment, and hence breaking down those tissues by destroying the trophic 

 •functions. 



The progress and extent of the rot, then, in each berry, is in direct correlation 

 ■with the growth and vigor of the mycelium; and when the growth of the mycelium 

 for any reason becomes checked, the progress of the rot is checked at the same 

 time. In passing through a vineyard one may find berries in which the rot has been 

 checked in all stages, from a minute speck to a spot equal to one eighth or a quar- 

 ter of the berry. In such cases the berry goes on to maturity as though nothing had 

 happened, except that it carries this dark scar upon its cheek. Even when one-half 

 or more of the berry has rotted, the remaining portion may go on to maturity, but 

 the nutrition is so impaired that it frequently shrivels up, though the decay proceed 

 no farther. 



Now a proposition which we wish to submit is, that fructification of the fungus 

 checks the growth of the mycelium; hence checks the progress of the rot in that 

 particular berry. Conversely, that checking the growth of the mycelium hastens 

 fructification; from the fact that it draws the attention of nature to the necessity of 

 accomplishing this crowning act before it is too late. 



Observation bears out this proposition. 



All observers agree that fructification of this fungus takes place in four forms; 

 but no single observer has ever been able to identify all four of the forms. Scrib- 

 ner found two of them only in his own researches. Mr. Erwin Smith is his author- 

 ity for the third; and the fourth was observed by him in a specimen furnished him 

 by Mr. Ellis. 



In examining a large number of specimens, the writer was able to observe only 

 two of the forms — the same described by Mr. Scribner. 



When the mycelium is checked in its vegetative career by the stimulus of nature 

 to prepare for the crowning act of its life, it bends its energies to the production 

 and growth of little perithecia or capsules for the protection of the spores which are 

 destined to occupy them. 



Two forms of perithecia are now produced directly from the mycelium, immedi- 

 ately beneath the epidermis, bulging it up in minute elevations which give to the 

 surface a pimpled appearance. Of the two forms, the pycnidia are the larger, more 

 scattering, and earlier in appearance; the sperniagonia the smaller, more closely ag- 

 gregated, and by far the more numerous. The spores contained in the pycnidia are 

 called stylospores; because they are borne upon little styles seated upon the base of 

 the capsule. They are extruded through the raised epidermis by the flow of the 

 viscid contents of the capsule through any rupture in its surface. The spermagonia 

 contain minute spores called spermaUa, because there is at least a probability that 

 they are the male element of reproduction. If this be the case, analogy and the ex- 

 isting conditions suggest that the stylospore of the pycnidia are the female element. 



Scribner says: "Not infrequently the first evidence of the disease is the sudden 

 appearance of one or more circular, slightly-depressed spots of a bluish-black color, 

 in the center of which there soon appear a few of the little pimples or pustules re- 

 ferred to. These spots increase in size, the pimples in number, and ere long the 

 berry exhibits the usual black and shriveled appearance." 



The observations of the writer do not corroborate this statement. Wherever 

 these blue spots were found, and they were not infrequent, they were never observed 

 "to grow larger, although the number of pimples might increase. The appearance of 

 tfhe spermagonia upon the surface in the shape of pimples seemed to be a signal for 

 the advance of the rot to cease, and the portion which had already rotted to become 

 bluish black and shriveled. The pycnidia may occur earlier on the smooth brown 



