The Securities and Exchange Commission has not necessarily reviewed the information in this filing and has not determined if it is accurate and complete.
The reader should not assume that the information is accurate and complete.

UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549
FORM 13F

FORM 13F INFORMATION TABLE
OMB APPROVAL
OMB Number: 3235-0006
Estimated average burden
hours per response: 23.8
COLUMN 1 COLUMN 2 COLUMN 3 COLUMN 4 COLUMN 5 COLUMN 6 COLUMN 7 COLUMN 8
VALUE SHRS OR SH/ PUT/ INVESTMENT OTHER VOTING AUTHORITY
NAME OF ISSUER TITLE OF CLASS CUSIP (x$1000) PRN AMT PRN CALL DISCRETION MANAGER SOLE SHARED NONE
3M Company COM 88579y101 16,086 113,464 SH   SOLE   0 0 113,464
Abbott Labs COM 002824100 579 14,388 SH   SOLE   0 0 14,388
Abbvie Inc. Com COM 00287y109 773 14,214 SH   SOLE   0 0 14,214
Apple Computer COM 037833100 5,863 53,155 SH   SOLE   0 0 53,155
Auto Data Processing COM 053015103 16,901 210,318 SH   SOLE   0 0 210,318
BB&T Corp. COM 054937107 405 11,390 SH   SOLE   0 0 11,390
Becton Dickinson COM 075887109 272 2,051 SH   SOLE   0 0 2,051
Bellicum Pharmaceutica Com COM 079481107 244 16,770 SH   SOLE   0 0 16,770
Berkshire Hathaway Cl B COM 084670702 267 2,045 SH   SOLE   0 0 2,045
Black Stone Minerals L Com Uni COM 09225m101 980 70,998 SH   SOLE   0 0 70,998
CVS Health COM 126650100 11,941 123,766 SH   SOLE   0 0 123,766
Chevron Corp COM 166764100 1,749 22,176 SH   SOLE   0 0 22,176
Coca-Cola Co COM 191216100 15,600 388,842 SH   SOLE   0 0 388,842
ConocoPhillips COM 20825C104 272 5,676 SH   SOLE   0 0 5,676
Donaldson Inc COM 257651109 14,413 513,275 SH   SOLE   0 0 513,275
Dorchester Minerals LP Com Uni COM 25820R105 767 53,023 SH   SOLE   0 0 53,023
Dover Corp COM 260003108 11,526 201,581 SH   SOLE   0 0 201,581
Echelon COM 27874n105 32 54,162 SH   SOLE   0 0 54,162
Ecolab Inc COM 278865100 19,027 173,412 SH   SOLE   0 0 173,412
Emerson Electric Co COM 291011104 11,247 254,629 SH   SOLE   0 0 254,629
Exxon Mobil Corp Com COM 30231g102 2,733 36,756 SH   SOLE   0 0 36,756
FedEx Corp COM 31428x106 15,814 109,832 SH   SOLE   0 0 109,832
Halcon Res Corp Com New COM 40537q209 139 262,222 SH   SOLE   0 0 262,222
Illinois Tool Works COM 452308109 16,661 202,422 SH   SOLE   0 0 202,422
Intel Corp COM 458140100 16,720 554,730 SH   SOLE   0 0 554,730
International Business Machine COM 459200101 567 3,911 SH   SOLE   0 0 3,911
Johnson & Johnson COM 478160104 16,453 176,247 SH   SOLE   0 0 176,247
Luminex Corp Com COM 55027E102 662 39,175 SH   SOLE   0 0 39,175
Medtronic PLC COM 585055106 607 9,069 SH   SOLE   0 0 9,069
Microsoft Corp COM 594918104 17,190 388,389 SH   SOLE   0 0 388,389
National Instr Corp COM 636518102 12,218 439,641 SH   SOLE   0 0 439,641
Nokia COM 654902204 102 15,100 SH   SOLE   0 0 15,100
Nordson Corp COM 655663102 17,555 278,924 SH   SOLE   0 0 278,924
Novartis AG COM 66987V109 16,646 181,095 SH   SOLE   0 0 181,095
Paccar COM 693718108 12,673 242,919 SH   SOLE   0 0 242,919
PepsiCo Inc COM 713448108 16,122 170,965 SH   SOLE   0 0 170,965
Phillips 66 COM COM 718546104 218 2,843 SH   SOLE   0 0 2,843
Procter & Gamble COM 742718109 14,956 207,898 SH   SOLE   0 0 207,898
Sabine Royalty Trust UBI COM 785688102 428 14,000 SH   SOLE   0 0 14,000
San Juan Basin Royalty Trust COM 798241105 6,125 647,452 SH   SOLE   0 0 647,452
Schlumberger Ltd COM 806857108 11,770 170,655 SH   SOLE   0 0 170,655
Stericycle Inc Com COM 858912108 242 1,740 SH   SOLE   0 0 1,740
Telefonica de Espana COM 879382208 491 40,779 SH   SOLE   0 0 40,779
United Parcel Svc Cl B COM 911312106 14,774 149,697 SH   SOLE   0 0 149,697
W.W. Grainger COM 384802104 18,176 84,538 SH   SOLE   0 0 84,538