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 15,382 112,682 SH   SOLE   0 0 112,682
Abbott Labs COM 002824100 1,190 15,078 SH   SOLE   0 0 15,078
Abbvie Inc. Com COM 00287y109 1,115 14,639 SH   SOLE   0 0 14,639
Adobe Sys Inc COM 00724F101 248 779 SH   SOLE   0 0 779
Advanced Micro Devices COM 007903107 312 6,855 SH   SOLE   0 0 6,855
Alcon COM H01301128 9,986 196,496 SH   SOLE   0 0 196,496
Alphabet Inc Cap Sk Cl A COM 02079k305 882 759 SH   SOLE   0 0 759
Amazon.Com COM 023135106 3,053 1,566 SH   SOLE   0 0 1,566
Apple COM 037833100 16,238 63,855 SH   SOLE   0 0 63,855
Auto Data Processing COM 053015103 27,878 203,963 SH   SOLE   0 0 203,963
Becton Dickinson COM 075887109 16,976 73,882 SH   SOLE   0 0 73,882
Berkshire Hathaway Cl B COM 084670702 376 2,057 SH   SOLE   0 0 2,057
Black Stone Minerals L Com Uni COM 09225m101 704 150,357 SH   SOLE   0 0 150,357
Blackrock Inc COM 09247x101 260 590 SH   SOLE   0 0 590
CVS Health COM 126650100 10,150 171,077 SH   SOLE   0 0 171,077
Centene Corp Del COM 15135B101 232 3,905 SH   SOLE   0 0 3,905
Chevron Corp COM 166764100 1,871 25,816 SH   SOLE   0 0 25,816
Cisco Systems COM 17275R102 208 5,285 SH   SOLE   0 0 5,285
Coca-Cola COM 191216100 17,519 395,904 SH   SOLE   0 0 395,904
ConocoPhillips COM 20825C104 223 7,256 SH   SOLE   0 0 7,256
Donaldson COM 257651109 19,882 514,666 SH   SOLE   0 0 514,666
Dorchester Minerals LP COM 25820R105 488 52,423 SH   SOLE   0 0 52,423
Dover COM 260003108 17,708 210,955 SH   SOLE   0 0 210,955
Ecolab COM 278865100 26,345 169,061 SH   SOLE   0 0 169,061
Emerson Electric COM 291011104 12,489 262,104 SH   SOLE   0 0 262,104
Exxon Mobil Corp COM 30231g102 2,033 53,533 SH   SOLE   0 0 53,533
Facebook Inc Cl A COM 30303m102 336 2,016 SH   SOLE   0 0 2,016
FedEx COM 31428x106 13,679 112,809 SH   SOLE   0 0 112,809
Home Depot Inc COM 437076102 470 2,518 SH   SOLE   0 0 2,518
Honeywell International COM 438516106 16,598 124,063 SH   SOLE   0 0 124,063
Illinois Tool Works COM 452308109 27,057 190,383 SH   SOLE   0 0 190,383
Intel COM 458140100 28,544 527,428 SH   SOLE   0 0 527,428
International Business Machine COM 459200101 353 3,182 SH   SOLE   0 0 3,182
Intuitive Surgical COM 46120E602 1,077 2,175 SH   SOLE   0 0 2,175
J.P. Morgan Chase & Co. COM 46625H100 432 4,799 SH   SOLE   0 0 4,799
Johnson & Johnson COM 478160104 23,178 176,758 SH   SOLE   0 0 176,758
Lam Research Corp. COM 512807108 411 1,711 SH   SOLE   0 0 1,711
Lockheed Martin Corp COM 539830109 250 737 SH   SOLE   0 0 737
Lowes Cos Inc COM 548661107 347 4,027 SH   SOLE   0 0 4,027
Luminex Corp COM 55027E102 888 32,272 SH   SOLE   0 0 32,272
Mastercard Inc Cl A COM 57636q104 1,093 4,526 SH   SOLE   0 0 4,526
McCormick COM 579780206 15,692 111,122 SH   SOLE   0 0 111,122
Mcdermott Intl Inc Com COM 580037703 1 24,885 SH   SOLE   0 0 24,885
Medtronic PLC COM g5960l103 696 7,716 SH   SOLE   0 0 7,716
Merck & Co Inc New COM 58933Y105 359 4,663 SH   SOLE   0 0 4,663
Microsoft COM 594918104 57,271 363,139 SH   SOLE   0 0 363,139
Mondelez Intl Inc Cl A COM 609207105 336 6,716 SH   SOLE   0 0 6,716
National Instr COM 636518102 15,782 477,075 SH   SOLE   0 0 477,075
Netflix Inc COM 64110L106 826 2,200 SH   SOLE   0 0 2,200
Nike Inc CL B COM 654106103 261 3,156 SH   SOLE   0 0 3,156
Nokia COM 654902204 47 15,250 SH   SOLE   0 0 15,250
Nordson COM 655663102 34,037 251,996 SH   SOLE   0 0 251,996
Novartis AG COM 66987V109 16,591 201,220 SH   SOLE   0 0 201,220
Paccar COM 693718108 15,198 248,620 SH   SOLE   0 0 248,620
Paypal Hldgs Inc COM 70450Y103 328 3,430 SH   SOLE   0 0 3,430
PepsiCo COM 713448108 20,233 168,466 SH   SOLE   0 0 168,466
Pfizer, Inc. COM 717081103 251 7,687 SH   SOLE   0 0 7,687
Phillips 66 COM COM 718546104 332 6,188 SH   SOLE   0 0 6,188
Procter & Gamble COM 742718109 22,955 208,685 SH   SOLE   0 0 208,685
Sabine Royalty Trust UBI COM 785688102 387 14,000 SH   SOLE   0 0 14,000
Salesforce Com Inc COM 79466L302 288 2,000 SH   SOLE   0 0 2,000
San Juan Basin Royalty Trust COM 798241105 1,360 647,452 SH   SOLE   0 0 647,452
Select Sector Spdr Tr Sbi Int- COM 81369y886 219 3,954 SH   SOLE   0 0 3,954
Taiwan Semiconductor COM 874039100 14,225 297,650 SH   SOLE   0 0 297,650
Telefonica de Espana COM 879382208 129 28,192 SH   SOLE   0 0 28,192
United Parcel Svc Cl B COM 911312106 5,274 56,458 SH   SOLE   0 0 56,458
UnitedHealth Group Inc COM 91324P102 481 1,927 SH   SOLE   0 0 1,927
Vanguard Index Fds Reit Viper COM 922908553 212 3,032 SH   SOLE   0 0 3,032
Vanguard World Fds Inf Tech ET COM 92204A702 408 1,924 SH   SOLE   0 0 1,924
Verizon Communications COM 92343v104 368 6,855 SH   SOLE   0 0 6,855
Walt Disney COM 254687106 440 4,559 SH   SOLE   0 0 4,559
Waste Management Inc Del COM 94106L109 324 3,500 SH   SOLE   0 0 3,500